1. nope -- the foam floats hardly never need replacing -- I guess they could get saturated or something, but feel comfortable ordering the kits without floats.
2. I've used Sierra kits many times, never a problem.
I think Jtexas is correct. The floats hardly ever fail unless damaged in some way. I am temporarily using the carbs from my 1989 Evinrude 88 v-4 on my 1996 Johnson 88 V-4 and they are still working great. I don't think your going to have any problems with third party rebuild kits. I too am using the Sierra kits without any problems.