#1
would sweeping behind a tapping lick sound strange
if its played in the right key
im not sure if it be to much
#2
You could write a harmony part where one guitarist is sweeping and another is tapping.

It could be like this:

Guitar 1
e-t12p8p5 t12p8p5-

Guitar 2
e-5----5-----
B---6----6---
G-----7----7-