You know the thoughts and opinions of everyone that replied on here. Just cause you don't like them doesn't make it any less true.
Whether your building a team, employing subcontractors, getting friends, or whatever idea you flip flop to, you're in no position to be leading a loft conversion. You keep saying you have friends in the know. Well you should be giving this project to these friends and be part of their team to learn. You don't know what you're doing for a conversion, not even remotely, but you've arrogantly decided you're going ahead regardless and don't accept/understand why people are telling you it's got trouble written all over it.
I'm done wasting time on this thread. You do you. Hopefully your client doesn't take you to court for a botched conversion cause your subcontractors won't give you a second look when it comes to it.