Converting to FG means solving the chainline problem. In short this usually means both trying to bring the bring the chainring in as tight as possible and then respacing/redishing the rear wheel as much as necessary to meet the chainline given by the chainring.

Therefore, pick the bike (or perhaps the crankset) that allows the most options for moving CL in. Chainrings that can be unbolted and shifted to the inside of the spider arms is good.

jim