No. Transfems are developing more sensitivity as their breasts and nipples are developing. Us transmascs went through that same thing during puberty number one. It doesn't reverse, the tissue and nerves have already grown. 

It's very common to not get full sensitivity back after top surgery though,  and some people lose all sensitivity post op.

If I had to take a guess, I would say yes. 

However, this is entirely based on how most effects of E are the opposite for T and vice versa, but there could be an exception for this

So, i know transfems on HRT in most cases have sensitive nipples like afab people. Do transmascs lose that sensitivity on T?

Can T reduce sensitivity?