I can't address the nose gear fairings, because I don't have any, but I do use rivnuts to secure my transition fairings for the main gear. No issues at all. The key with rivnuts is not to over torque them or use them in any structural capacity. I simply installed them into the fuselage skin with no backing.
RV-8 #81077 Super Slow Build
Titan IOX-370, Dual P-Mags, AFP FM200A FI, Whirlwind 200RV CS Prop
First Flight 11/20/2016