Hi there everyone

I think I've got a plan of action for a trip to the US later this year, but I wanted to run it past you all to see if there's something I've missed - any suggestions gratefully received.

I'm taking my mother on a sort of once-in-a-lifetime road trip taking her to the Grand Canyon, Arches National Park, and the like, followed by catching the solar eclipse in Wyoming later this year. In practice that means flying to Lon Angeles, or Las Vegas or somewhere like that, and returning from Denver.

I've got a shed load of points and a companion voucher to offload, and would like to travel in as much style as possible.

We've come across (of course) availability issues at this short notice for reward flights, so what I've done is this:

2 economy reward flights using a companion voucher from LHR to LAX on BA
2 economy paid for flights from DEN to LHR on Icelandair on a flexible ticket that can be cancelled

If i've understood the way things tend to work correctly with reward flights, there are only a small number released a year in advance and then close to the date of the flight they open up more if there's space on the plane - is that right? So on that basis, I should be able to cancel my Icelandair flights (paying a £30 fee), cancel then rebook the BA flight along with the BA equivalent open jaw return, if there is reward availability. Is that right?

Even if no availability comes up for the return from DEN, if my outward bound flight to LAX gets availability in a higher cabin, I should be able to cancel and rebook in a higher cabin, correct?

I've got the points and the vouchers, and there are BA flights there that I want to take, I just wanted to know whether what I had planned was possible, if availability was there, or have I missed something that prevents me from doing it?

Any tips on how to get the best outcome are welcome, and sorry if I've asked the same question as someone did five minutes ago - i've been away from here for a while.

Thanks