RE: 3 ch to 4ch.??????
Consider the 3 channel Flylite before going to a 4 channel. After that perhaps a larger cub like the flyzone 3' or 4' one would be nice. The sensei and the switch are also nice 4 channel planes.
I just started on the FW190 from flyzone. I love it so far. I'd get that after the switch. You have 2 minis , that's probably enough if you're interested in progressing.