Depending on the circumstances your rights absolutely entitle you to engage in street fights with the police. It may not be wise, but you can do it legally (in some circumstances).

A couple of famous cases come to mind - Tupac, the rapper, was once driving down the street when he witnessed two police officers beating up a random guy. He grabbed his gun and engaged in a brief gun fight with the police. Completely justified at court.

Randy Weaver, at Ruby Ridge, was ambushed by federal marshals. In a gunfight he shot and killed a marshal and successfully argued it was justified at court.

You can legally fight and kill the police in some circumstances. It's dangerous, and you'd better be sure you're in the right, but it is legal.

(I'm also emphatically not saying you'd be justified in fighting the police over a face scan)

Depends on the circumstances, but not really.

Only if they have your prints to begin with.