The whole thing with Zick's dad being shrunken. That's no excuse for Zick not knowing about him.
Why didn't Greta give Elena the Gift of Sight, the ability to see monsters, earlier when she found out the monster world?
I think it's because she didn't chose her yet to give her that as she think she's not ready to see monsters. When Elena becomes too serious to rescue Zick, even though it's too dangerous, that's when Greta decided to give her the ability to see monsters in order to become useful in future episodes.
And obviously, the gift of sight isn't handed out like candy to everyone who knocks on the door. It's usually handed down from parent to child, so when she gave the gift to Elena, it's like Greta made her part of the family.
Even though she can't see monsters first, how come Elena can figure out who it was?
How did Zick gets his powers back when he sees Magnacat hurting his father?
It is when Zick's anger and rage on Magnacat that gets his powers back.
If Chumba is in Lardine's Detention Oasis, how come he is shown trapped in a Dom Box in season 2?
Why couldn't Magnacat see that Elena can see him in his monster form?
It is Elena's pretending that really did him.
Why does Bombolo poops or farts when he eats chocolate?
I think it is because it is his allergy.
Why can't Zick talk in his Bommerbang form?
Maybe it is because this monster breathes fire. Since Zick doesn't know about his powers in that form, I guess he will breathe fire every time he opens his mouth.
It bugs me how the entire Monster Allergy thing was written on TV Tropes. Don't get me wrong, I like the series (in fact, lack of popularity bugs me too), but the whole way the Nightmare Fuel, the Bugs Me page and etc. emerged on this site seems to had been written by a bunch of rabid little kids who simply wrote everything to make the premise sound interesting! I mean, the answers to this very own Bugs Me page were probably written by the same people who wrote the questions in the first place! Also, the "Nightmare Fuel" is a lot more like Nightmare Retardant; not only it is largely not very scary, it ISN'T SUPPOSED TO BE SCARY, because Italy is still way beneath the Animation Age Ghetto damn it!