Conrad doesn't actually think the aliens are fake. He knows for a fact that they are real. The point is that he is making his fortune by lying to his audience, spreading misinformation and distrust in the very people who he knows really are protecting them, but he doesn't care. It's pretty obviously based on a few real world people I can think of. Of course, there is also the complexity of some legitimate questions about how UNIT operates and what they are keeping secret. The fact that these questions are asked by someone who is also blatantly lying about what they do for personal gain adds some real thematic depth. The fact that there are real ability and transparency issues at UNIT that need to be addressed plays into Conrad's con. Conrad knows that aliens are real and that the Doctor is real both from personal experience and from his inside guy at UNIT, who he is also shown to have lied to, used, and abandoned because he's only interested in his own power and wealth. The cost to anyone else is of no importance to him.

I like it! I didn't catch that and it could genuinely be a throwaway line that doesn't mean anything more, but if you're correct it opens up so many possibilities for what will be revealed. Here's one: reality war is the version of the time war in another reality where Gallifrey _is_ named Timelordia. Their version of Davros (or equivalent) makes a successful reality destroying weapon. Time Lords can hold off their own destruction for a while but it's inevitable, so, being Time Lords they try to save themselves regardless of cost to everyone else by finding a new reality (the Doctor's) to move to/take over. The Doc is either the key to this or the only thing that could stop it, so they send an agent (Belinda chameleon arched) to various times/places to encounter him and get him to the right time/place (why she's so insistent to return to the exact date of her new "shift"). Also, maybe Belinda's true Time Lord persona is "The Boss", a Time Lord we haven't met before, trying to connect to the Doctor by getting her agents, like Meep, to look for beings with two hearts. The Tardis is preventing him from going there because it knows what will happen. Meanwhile Mrs. Flood is the god of stories. She doesn't write them, she just knows all stories (how she knows the Doctor's end), but just like time, stories can be rewritten. She's not an enemy like the other gods. She's simply showing up where she can see the stories play out. She breaks the 4th wall because (as I think she'll explain to the Doctor when they finally meet), everything that's real in one reality is just a story in another reality. This is why the Time Lords, if they're even capable of feeling guilty, feel none for breaking this other reality. They may not realize that they'll destroy the Doctor's reality as well because if they can escape to it, their enemy probably can too.

There are a hundred other ways it could play out if you're right, of course (Belinda = Susan??)