Hey, thanks a lot to the community here for your help. I've answered the questions below. Our BA silvers expire this year but we've got a couple TATL cash J trips planned in the next few months, so we're figuring out what to do. We can choose the airline for these. Thanks!

(1) What is most important to you in a FFP?
US domestic lounge access, premium seat selection (e.g. AA MCE)
(2) How many miles do you usually fly each year & in what class? How many flights/sectors?
JFK<->LHR 2-3 times per year in cash business. Then 10-20 sectors in US domestic economy on vacations. I'm a Brit living in NYC. Other long haul trips would like be award flights so not relevant here.
(3) What types of fares do you usually buy?
Business for TATL (company pays), economy SH/PE LH if I'm paying.
(4) Can you choose your airlines and/or class of service? Do you travel for work and/or pleasure?
Yes I can choose for work trips. I fly for both work and pleasure.
(5) Which routes and airlines do you fly most often?
TATL.
(6) What is your home airport?
JFK
(7) Do you have FFP status of any kind in OW or other airline? What is it? Do you have any miles banked in a FFP?
Myself and my wife both have BA Silver (OWS). This expires this year after a quieter year of travel, but we have multiple cash business TATLs planned in the next 6 months.
(8) Preferred Airlines? Most common Airlines flown on?
Only ever flown BA TATL. It's fine, happy to try something else if it's better.