INV-LAS TP run/holiday booked 28/10-15/11

Had an email from BA informing me flight from JFK-LAX has been cancelled and have been rebooked.
First problem is arrive from HEL on AY but AA 8985 into JFK 1540 and originally booked on AA306 1700 to LAX (realise now MCT may be the cause of cancellation) HOWEVER new flight is AA 341 departing JFK 1430 (so 70 mins before I arrive !!)
So next available flight after 1700 is 1829 arriving LAX 2156 which means an overnight in LAX which I was trying to avoid.
Struggling to see alternatives as obviously want to keep my 880TP
Phoned BA and was told to wait until closer departure as schedules will no doubt change again - at this point I hadn’t realised the MCT was likely the issue and neither of us could work out why it wouldn’t show her the 1700 flight.
My questions are is MCT of 80 mins at JFK I-D too short (I think yes)
Any other suggestions ?
If I try to rebook HEL-LAS via different route ie HEL-LHR-LAS what are my chances of ORC?
Sorry if this is long winded but appreciate your time