The problem with the fiancee visa is that he won't be able to work here for two years I think? That would be extremely difficult....
No, that's completely not true.
The fiance visa does not allow work, but it is only valid for 6 months, during which time you must marry, and then he needs to switch to an FLR(M) visa after the wedding and before the 6 months are up. He can then work as soon as his FLR(M) visa has been issued.
So, if you were to marry within a few weeks of him arriving in the UK on a fiance visa, and then paid extra to apply in person for FLR(M) (which is a same-day decision and he'll get the visa within 10 days), he could be legally allowed to work within a couple of months of arriving in the UK.
Alternatively, if you do marry in the US, and apply directly for a spousal visa, he will be able to work immediately upon arrival to the UK, and it will save you the cost of paying for both the fiance visa and then FLR(M) visa after the wedding.