1) Those numbers are about American finance in 2011. British finance in 1991 probably did not have salaries quite that ridiculous. But more importantly:
2) As Dumbledore explains, it’s not this rescue price that is the problem, so much as all the cumulative rescue prices Harry’s enemies will now expect him to pay for each of his friends (not necessarily once, either… Hermione could well be attacked again).
Same. The part about disappearing in Albania is from canon-Quirrell’s backstory—that’s where he ran into Voldemort’s wandering ghost, so it’s interesting that in MoR he supposedly went there before the war. The rest of the background recounted by Bones and by Quirrell himself don’t really ring a bell with me, the closest thing I can think of is him needing “reconciliation” with the Lady of the House being reminiscent of Sirius Black and his spat with his family, but Sirius already exists in MoR and had a different history.
It might be possible that in MoR the house of Gaunt (the one canon!Voldemort is from) did not fall into poverty and retained their household and Wizengamot influence? If the general ‘powering up’ of characters can go that far back it would be plausible. And now that I think of it, Quirrell initiated talk about witch-on-Muggle magical seduction during the SPHEW arc, which could suggest that that part of his family background was carried over from canon.
(One of the things that annoy me about HPMoR is that when I can’t quickly figure out what a certain passage might be hinting to, I have to assign a frustratingly high probability to the event that it’s simply a reference/homage/in-joke to one of the myriad HP fanfictions.)