I can answer at least a few of these for you based on my own playtime. HTH..
- What is the most expensive configuration of the Fleet Carrier?
I ploughed about 7B to get everything running, left me with 2b [eek] but, as its beta, I'm loosing nothing really.
- How much reserver tritium can be accumulated, how many jumps worth?
1000 units can be stored on your carrier currently.
- Does the jump distance scale with the Tritium use or is it a "Flat fee" 10LY or 500LY - it still costs "50" Tritium, or whatever the max is.
Yes. I jumped about 7LY and used about 3 Tritium.
- Will we be able to store modules on the FC?
Yes, I've moved all 7 of my ships AND all modded modules ect to my FC.
- Our own ships?
Yes, but you need to install the ashipyard add-on [ridiculous though it seems... this IS, after all, a carrier?]
- If our own ships, how would we transfer them, same as the current transfer mechanic?
Yep
Fly safe, CMDR.