Translation:How am I going to get the children out of the museum?
"How am I going to take the children from the museum" should be accepted, I think? In certain contexts I think this would be the more natural translation. "How am I going to get the children out of the museum" almost seems like they're being held there against their will...
Or they are running around causing a huge mess, and you just can't get them.
There are over 250 uses of "get" in English. (I have a friend who authored that book). "Get" is exactly what most Americans would say. We wouldn't say "take".
Is remove an acceptable translation of tirar in most cases (like this one)?
That sounds like something that a newspaper would write with reference to crowd control: "The police removed the demonstrators from the building."
In many cases, yes.
I'm afraid saying most is too much....
ele tirou água da rocha (he took water out of the stone - it sounds a little odd to say he removed water from the stone).
ela tirou uma arma da bolsa (she took a gun from her purse - to say remove sounds a definitive thing).
Whereas in English it sounds a lot odder to say he took water out of the stone than to say he removed water from the stone. I assume it means he dried it.