I think they went for 'Ice Maiden' for Emma Frost but I agree she came across as too passive and lacking in any personality as a result.
If Cyclops was shown along with Storm in the Cerebro scan, why can't Havok just be Scott's older brother? I didn't notice Scott so I don't know how old he appeared but Storm looked perhaps 7 years old? I don't know at what age the USA imprisons people but assuming Alex was 18, his brother could be 10 years younger or less. Don't make it more complicated than it needs to be!
Moira's adjusted story - now that is looking a lot more complicated...
Professor X was also known to use a pyscically powered harness to walk for short periods in the comics. There's no need to get too hung up on that issue either.
I'm more concerned by moving from Zavier to Exavier. We aren't so dumb that we can't work out his name begins with an X!