Echo what the other folks say, just replace all 4 and sell on your redundant RFTs - rear tyres are usually easier to sell on anyway as they're replaced more often on RWD cars like ours anyway.
Non-RFTs like the Falkens have, by definition, softer sidewalls with more compliance. As cj10jeeper says, softer sidewalls (which is what makes them more compliant and comfortable) mean less bite in turn in, but this is marginal and I doubt most of us would notice much of a difference. Certainly, you can make more of a difference to the turn-in feel by changing the degree or toe and camber on the front wheels anyway.