My own FC doesnt't have shipyard too. I do not want to sell ships in predefinied packages which are not even engineered. Imho FC shipyard should offer possibility to sell or rent engineered ships- that would be real fun for me and probably other players like me who like to engineer ships too. I'm also thinking not only about credits but ARX since there alaways be players who would wish to buy something for real money (this could partialy limit shady and illegal business of selling ingame stuff for real money against EULA which I can see quite often in other games) and ARX sale could be taxed* (tax amount and top price specified by developer).
I do not know how hard would be to introduce ability to sell/rent ships for credits and/or ARX but I suppose some kind of survey from developer side would be required to see how many players would be interested in it and if it is an idea that would bring profit for both players and developers alike.
Edit: *Tax from salles might go into special pool which can be used to issue extra ARX rewards from participating in Community Goals activities, or to issue special rare missions randomly on in game mission boards.
In regards to main topic. Sharing ships: no (unless it is rental), selling engineered ships: yes, shared FC management: yes but not everything- some things like livery, services offered, services suspended should be managed by the owner, others like issuing jump command, managing market can be shared.