1. This is irrelevant.

No, it's not. If, conditional on me always rejecting the £10 when Omega makes this specific prediction, Omega would visit when the envelope was empty, offer £10 and make the different prediction that I'd take it (the assumption being that I wouldn't refuse it without reason so Omega can't make the true prediction that I'd do so), or if, conditional on me always taking the £10 when Omega makes this specific prediction, Omega would visit when the envelope was full, offer £10 and make the different prediction that I'd take it that would change the payoff. If only the first was true that would make the scenarios equivalent.

Omega snatches the £10 away from you, swallows his words, runs out and returns a bit later with a check for £100 000. "Out of deference to your uncertainties", he says, sighing, "I've decided to renew the experiment with a lesser ratio. But just this once!"

I take it of course.