The answer can by yes or no depending on specifics which you don't go into.
Silencers are not legal in the state of Iowa. Currently there are 39 out of 50 states that individuals, trusts and corporations can legally own silencers.
Depends on who is using them and for what.
Yes, provided you have complied with the FEDERAL law regarding suppressors. This is governed by 18 PA.C.S.§ 908.
Because they could easily be used as firearm silencers.
Suppressors are legal, yes.
Yes, silencers are legal in Nevada (assuming they are correctly registered with the ATF)
The local police can assist you.
Yes, an air rifle is not considered a firearm by Texas or federal laws.
Yes. Must be registered with the Federal BATF, but state legal.
Yes- see link at bottom of page.
Provided you comply with all the federal, state and county laws, yes.