Let's say Plan A - Lebron and Bosh doesn't work out, I'd trade for Kirilenko and his one year deal in lieu of signing a big time PF free agent to a five-year deal while waiting for Favors to develop.
After next season, Kirilenko comes off the books. If Favors has developed, AWESOME!! If not, they can re-sign Kirilenko or sign a different free agent.
I'd also target Rudy Gay in this scenario... he's very young, a 20 pt scorer and has the potential to be even better.