Welcome to Flyertalk rjdflyer, welcome to the BA forum. I hope you have an enjoyable retreat, I live not so far from Edinburgh. I hope we will see more of you here, so please make yourself at home here.

I can see there will be at least a dozen ways to play this scenario out and I am only competent to comment on a few aspects, so there's quite a lot of homework ahead of you. But to give a few pointers:

- If going the BA Avios route, with the Amex haul, bear in mind the lowest number of Avios happens if you go off peak and purely on BA metal, so that would be ORD-LHR-EDI. If you have to fly peak time then using AA to do something like DAY-NYC-LHR-EDI or via PHL or CLT is closer to the same cost as BA metal only.
- It may be cost effective to go ORD-EDI out and INV-ORD back, depends on the precise location of your retreat, I guess. This is due to a tax advantage that INV has in this scenario.
- Avios bookings are fairly flexible so you best book something soon and then be prepared to pay the change fee if a better option comes up.
- Iberia can give better value for money with Avios across the Atlantic, it's the same system and can be inter-changed with BA Avios after the IB+ account has been running for 90 days. It may be worth crediting a hotel stay or something similar to IB+ to get that clock ticking so you have the flexibility later. However the routing via MAD isn't a convenient one.