I'm okay with FrankenStarbuck in theory, though the problem of explaining how a crashed but recognizably intact Viper ended up on "Earth" is a big issue, since the VFX in Malestrom showed her Viper exploding into fragments.
The thing is, this could be used to tie-in with an explanation of the Final Five - Starbuck might not be merely a clone, but could in fact be the true Starbuck's mind and personality transferred into a new body with whatever step-up in technology over the regular Cylons that the Final Five seem to represent.
As for Not Earth, well... it's all in the presentation. The possibility for total failure in storytelling looms large, but with the correct nuances it could work. I'm not adverse myself to the idea that the ruined Earth is the "real" Earth and the one that we're living on (in the real world) is part of the "this has happened before..." cycle, where the 13th tribe fled after a war to find a new home.