Whew!
I made Franklin sleep in the kitty room alone last night just so Chelsea could have some peace and he didn't like it one bit! Meowed and meowed most of the night, poor baby. However, I found my Feliway so I sprayed the area like crazy plus I did the "rub the towel on one then rub the same towel on the other" trick several times. This morning he was so glad to be let out! And no issues with Chelsea so it looks like were back to normal.
Thanks for all the input!