Those books Shitari is always referencing? A copy of the Shiba clan's records. How'd he get that? In the raid that killed Takeru's father. That's why the book is so battered and worn.
So if as implied (and outright stated in Mako's case), several of (if not all) the Skinkengers have Samurai parents who fought alongside Takeru's father, why don't the Skinkengers know each other from childhood? The same reason we don't see Chiaki's two friends after Act 03 and Jii sees his family so rarely. To stop them from being drawn into the conflict with the Gedoushu. Takeru was only close enough for his dad to pass on the title of Shinken Red because he was the next Lord's shadow, and they were in place for just that situation..
Notice how a lot of Ayakashi seem pissed as hell to enter their second life. Despite angry threats from enlarged monsters are just a usual trope of Super Sentai, it actually makes sense here; despite the scale and power increase, they're that much closer to destruction. In fact, by the show's own canon, they've already died once. And they know the next time, it's Game Over.
As of Act 44 and 45, Takeru's reluctance for the others to risk their lives for him take on a whole new meaning. Simply put, since Takeru is only an acting lord until Kaoru was ready to establish her lordship, he felt that there was no need for his vassals to fight so hard for a fake lord.
Various bits of dialogue and scenes take on a new context after The Reveal. There are several Chekhovs Guns sitting around the show, and not just in regards to Takeru being Kaoru's kagemusha. Damn, Kobayashi's good!
Takeru bitterly refuses Jii's suggestion to summon the vassals in Act 1. Why? The same reason he apologizes to them in Act 45: They shouldn't be risking their precious lives for a substitute like him.
In fact, both of Jii and Takeru's conversations bookending Takeru's opening scene Badass display take on new meaning: Why was Jii intent on to formally introducing Takeru as lord? To make sure the Gedoushu saw him as the lord. So Takeru's not only re-acting to the ham, he's also responding from his insecurities as a kagemusha.
The scene where Shishi Origami is handed off to Takeru in the burning mansion: While it initially looked like a Take Up My Sword moment, it turned out to be a father's last moment with his son.
And off the bat, Takeru tells the vassals they need not think of him as their lord.
Act 12: When Jii addresses the armor in the mansion's common room. The secret plan isn't the sealing character; it's Takeru taking Kaoru's place.
Even certain character interactions can be seen in a new light— compare and contrast Kotoha and Takeru's backgrounds— no wonder one of Takeru's most touching rallies from a Heroic BSOD is from her inspiration— he can feel the parallels and gather hope from it. His constant attempts to get Ryunosuke to tone down the dramatic displays of loyalty. His cagey attitude when Mako attempts to understand him. His initial harshness to Chiaki, so lax when Takeru has had to give up so much. Yeah, Kobayashi and the rest of the staff, cast, and crew hit this one out of the park..
Don't forget when Takeru initially doesn't want Genta to join, both because he doesn't want to put Genta in danger and because he's afraid that having his childhood friend around will make it harder to keep up his "Distant Lord" persona. Each of these reasons are more significant with the secret plan in mind. For one, Takeru especially doesn't want Genta to die protecting a fake lord. Additionally, Genta might indeed hinder him in keeping the kagemusha act up.
Here's another Super Sentai one: I, like a lot of fans, wondered how Kaoru could just leave Takeru after adopting him in the finale of Samurai Sentai Shinkenger. She always wanted to know what her shadow was like, and didn't she want to know her new son? Then it hit me — this was the ultimate sign of respect. By leaving him after adopting him and making Takeru the 19th head of Clan Shiba, Kaoru is trusting Takeru to actually serve as a worthy head of clan. He doesn't need her hovering over his shoulder. He can do it, and she trusts him to — as sure as he trusts Tanba to take care of his adoptive mother. Perfect Samurai behavior.
Dokoku is extremely arrogant, believing few would have the nerve to defy him. He also doesn't care who serves him or what methods they use as long as they cam further his goals. Akumaro plays on these, acting subservient, demonstrating his power and even letting Dokoku strike him, which is why Dokoku accepts his services even when he seems so transparently treacherous that even Shitari distrusts him.
Looking at the character page I noticed that everybody has a Meaningful Name specially relating to their element. This is makes a lot of sense if one considers that in medieval times the use of last-names or family names was not common and usually done only by important families. It's entirely possible that the Samurai families named themselves after their elements during the reformation of Japan or when they became important
Whenever the group does their team roll-call, each Shinkenger does a specific, routine pose when announcing themselves (Ryuunosuke's hand by his face, for example)...except for the undisciplined Chiaki, who does something different practically every episode.
During Takeru's last battle with Juzo the background disappears becoming completely black, the only thing visible being Takeru, Juzo and the Flames. It's all very similar to the scene of Dayu's fall, because it means that Takeru was going to fall to Gedou.
That's 'fridge?' The red monster-coming-thru-cracks light rising just like during Juzo and Dayu's Start of Darkness flashbacks made it clear that Takeru was in danger of pretty much becoming the next Juzo. If he'd fought in anger instead of for justice, he'd have never stopped.
If the Shiba mansion is protected from Gedoushu by Mojikara, how did Dokoku stage the raid that killed the previous head and crippled Mako's mother?
His actual display of power in Act 40 might be a good "hint". We don't get to know how strong the Moji is; it certainly can block the Nanashi and Ayakashi, but also possible is that they just don't opt to blindly raid the mansion with 6 Samurai and several anti-Gedoshu precautions inside.
Where did Juzo get his horse from in Act 46? Takeru's horse is the same one he always summons with Mojikara, but how did Juzo get his?
In the first episode, Jii has both sharp and suction cup arrows at his disposal to send messages to the vassals - Kotoha gets the only suction-cup one, but the one fired towards Mako, in a location where she's surrounded by children, is the lethal type...
Given the distance travelled, the arrows seem to be guided by Mojikara or magic of some kind. Thus, the arrow was unlikely to hit anything (or anyone) that would cause a lot of trouble. And odds are he used the suction cup arrow on Kotoha because, as farmers, her parents might not have the resources to repair/replace anything that was skewered in the process of summoning her.