It says that cards must be sleeved, do your plots, house card, and agenda also have to be sleeved?

Please don't take this as an official response, since I'm not a TO or judge or anything. But I don't think people would be too put out if your plots/agenda/house card were unsleeved. They are not obviously covered by the intention of the rule.

Heck, at the last tournament my house card was made of 3/8" thick orange resin and no one minded. (I didn't sleeve it, either!)

Probably depends on people who organize your tournament, 'cause there are rules which most people don't even care about (such as defining first player for setup purposes and triggering preplot events, such as Citadel Law). But to avoid any possible hostility/accusations/fury/etc., I'd sleeve everything you can (especially, the resin House card! :-P )

True - there are a few things that can force you to choose a plot at random. I am not aware of anything that could affect your Agenda, though.

Resin house cards should be sleeved in saran wrap with a light coating of baby oil. "Sure, you can take power from my house…if you can hold onto the tokens!"