Funk/R&B is a difficult genre to quantify. Most of these groups aren't that funky; more mainstream R&B. The funkiest is surely Dazz. Maze is really more Pop. Most of the others use too much synth for me to put them in the category of groups that use classic instruments. Following Dazz I'd have to say Skyy.
I don't have time to go through the rest individually but of the list it's Dazz then Skyy.
Of course, the best R&B/Funk band of the 80s and all time is EWF.