I have this idea for Fallout Au, a while back, and I can’t stop thinking about it.
Where instead of Roosevelt being dead, he’s just been used as in experiment for the enclave for side project in human mutation. He becomes a hybrid. That’s where he meets CX404 (Dogmeat) and Siggi Wilzig. Four is also part of the hybrid experiments. Expect she’s sorta of runt.
Wilzig sees the wrongdoings of these experiments on the children hybrids, so he shelters them in his private lab while training them up. At some point he secretly comes into contact with Moldaver and also learns about the Three Vaults in Los Angeles, Moldaver's close ally (Probably lover) Rose MacLean.
Like in the show, Wilzig does further tests on the cold fusion tech and enjoying Four’s company, thats when an administrator walks in and catches Siggi covertly working on technology that the Enclave wasn’t privy to. Four and Roosevelt defend Wilzig, attack the administrator and kill him, kickstarting their escape. They leave the enclave, which as result turns them into fugitives. A bounty gets put on all three of them.
Roosevelt is only following them around because he’s slightly attached to Four, that and because Wilzig told him that Moldaver might have information on where to possibly find his family.
This what I think Roosevelt and Four would look like as hybrids. ⬇️
(I was slightly inspired by sweet tooth)