This is a "Wild Mass Guess" entry, where we pull out all the sanity stops on theorizing. The regular entry on this topic is elsewhere. Please see this programme note.
Lelouch is manipulating the situation to have Hisana and Byakuya fight Koga together
He would never never never EVER have him or anyone else kill his godchildren. Therefore I think he wants Hisana to think they are dead and have her fall into despair, which she would, and then go after Byakuya when she finds out it's not true only for Byakuya to already be in the world of the living and the two fight together side by side and husband and wife.
Lelouch has a special plan for Tekubi-kiri Tamashi to do
During the moment where Lelouch has to prove his "loyalty" to Muramasa, all that we see Lelouch do to Tekubi-kiri Tamashi is that he teleported him and Tekubi-kiri Tamashi out of the hideout and see that his moment to "break" her was off-screen. Speculation? He Geassed her to return to Nemu and to ask her to help him follow his plan and the reason we see her broken form and hear the trembles is because he needs to make the beatings look convincing so that Muramasa and the other Zanpakuto will be convinced that she's dead and won't think that she will be a threat to their plans until it is too late.
Not in the way you speculated, but still confirmed.
Kendra is in love with Ichigo but sadly can't be with him since he's still Orihime's boyfriend
During their close conversation of chapter 103 where she tells Ichigo the theory that he's Dead All Along she's strangely close to someone she barely knew, her strange eagerness to go meet up with him before he leaves Soul Society despite the reputation that her Squad is usually antisocial, the way that she seems more friendlier with him than usual when she came to his school in chapter 106, and currently the fact that after he takes her out into the town to teach her what people in modern times does in their spare time and when he said that he only sees them as just friends and then see Kendra break down in tears, it's pretty obvious that she developed romantic feelings for him. The big question here is, will she accept Ichigo only as a friend or will she think of trying to steal him away from Orihime? Only time will tell.
Lelouch is the Soul Chess universe equivalent of Roy Mustang
With what Susanna said of Lelouch's future ambitions way back in chapter 56 during Susanna's pregnancy, she said that Lelouch's future ambitions is to rise even further into the highest position of power possible as possibly the new Head Captain, a part of the Royal Guard, or even succeed the Soul King himself. Why is he determined to rise to the very top? As a part of his character, he just can't stand seeing the weak suffer while the strong either oppress the weak or does nothing to help make the weak live more better. Compared to Britannia, Soul Society is surprisingly more peaceful and reasonable in its rules but it still has a long way to go before it truly deserves the title of being a paradise for all. With all of the greatest achievements Lelouch has done throughout his years in Soul Society namely his Sorting Algorithm of Hollows, his time as Zero and as the leader of the Phantoms of Justice in which it helped spread his and the Phantoms' popularity, the unexpected death of Aizen, his strategic planing of taking down Talbumosuke and his forces, standing up against Central Forty-Six and reformat the crime laws, and currently, sacrifice his reputation to help Byakuya, and judging by the fact that we're still nowhere close to reaching the ending yet, Lelouch is destined to do even more incredible things that would make even Yamamoto possibly consider to choose him as his successor in case if something bad were to happen to him. Lastly, Lelouch's reasons for rising to the top of the chain in Soul Society could be seen as a way for him to atone for all of the major mistakes he made in his life. Like Roy Mustang, he knows that there will be plenty of people who won't forgive him for the terrible things that he has done in the past, but he won't give up hope and he is all the more determined to make Soul Society the peaceful afterlife that every unfortunate soul who passed on deserves.
Lelouch will be given a second chance to restart the House of Lamperouge and start over from scratch
Sure, the creator said that he trolled us from seeing this happen, but that doesn't mean it would be the last troll he'll pull and since we're still early into the story, it could possibly not be permanent and things may change and this would NOT be the last twist, turn, or trolling we'll see. One possible theory is that if the Aizen's Revenge arc gives any possible indication, Aizen will plan his revenge by escaping Hell and attack Seireitei so badly that it left Seireitei completely devastated with lots of casualties which would also possibly leave the other captains either dead, incapable of fighting back and/or forced to retreat and going into hiding but that leaves Lelouch as the only captain left to stop him since he's the one who has earned Aizen's wrath since his unexpected death by his Geass greatly hindered his plans and wants to avenge his loss. After Aizen's defeat and when Lelouch saves Soul Society again, the surviving captains decide to go to the surviving members of Central Forty-Six and try to appeal to them to expunge Lelouch's record to give him a second chance to restart the House of Lamperouge with a clean slate since without Lelouch, Soul Society would fall into disaster in Aizen's hands and having this happen is the least that they could do to repay him. Central Forty-Six should also realize that despite that Lelouch could have removed them entirely during the Lelouch and the Law arc, they are still there and in a sense, they kind of owe Lelouch their existence and gratitude as well. Once when Central Forty-Six tells Lelouch that they have now wiped his slate clean and has given him a second chance to restart the House of Lamperouge and ironically told him the same words he told them: "Lawbreakers are punished, good deeds and proof of change can be used to allow one the right to a second chance, though third chances are the ideals of a fool." In other words, he's given a second chance and he better not waste it and if Lelouch's love life gets much more hectic than before to the point he can't bring himself to only choose one, this is what he greatly needs.
Technically confirmed later, when his family starts arriving in Soul Society during the Black Rebellion; with Senna's backing, he and Clovis are building it anew, Euphie's obviously a member, and both Marrianne & CC have been let in. He later marries Shirley as well. Presumably Cornelia, Nunally and some others close to them (Suzaku, Kallen, etc) will be let in when their time comes.
Speculations on Kasumi's origins
Kasumi is Nemu's daughter
It was speculated that she was the result of a hollow impregnating a soul reaper. Remember what Mayuri did to her? This is the result.
Jossed, her DNA is that of being 3/4 Soul Reaper and 1/4 hollow. this would result of half and half.
Related trivia: Kasumi's original character (from Tales of Bleach) is Nemu's daughter.
Kasumi is the love child of Talbumosuke and Mia
In chapter 82 it is mentioned that Mia is ovulating and Talbumosuke has sex with her anyway. However, both of them die in the battle and the prospect of them having a child is lost. Kasumi is stated to have both hollow and Soul Reaper DNA. The only issue is the fact that she is a full grown woman and it hasn't even been nine months since the second battle. However, Lelouch's words at the end of ch 110 can be interpreted to lampshade this very fact. It's possible that, like Lelouch, Kasumi is also a Fish Out of Temporal Water. Whether or not she knows this or even knows of her origins remains to be seen.
Given Kasumi's brief encounter with the other two this is starting to become more likely.
It's now even more likely given her surname begins with 'A' and Orihime recognizes her last name.
Now that Kasumi's backstory is revealed, it just got even higher with the fact she was born in Hell.
Talbumosuke himself suspects this possibility. He may later ask her about it for conformation.
Lelouch's harem will end because of Aizen.
Since Anyone Can Die these days; it's possible the voting polls are for determining who Lelouch will marry by killing the other contenders. That means Yuna, Susanna or Nemu will likely die.
Jossed. They are all alive.
Confirmed insofar as Yuna breaks up with Lelouch almost immediately afterwards, and Lelouch eventually chooses Su.
Ichigo isn't really dead
For a few reasons:
The statement he would not rise to fight Britannia again could mean that he just gave up