Who knows about bathtub installation?

If you omit the overflow, you should have some method of dealing with a flood - eg a floor drain. Otherwise you are asking for trouble. Otherwise you only need the drain and trap, and the taps or valves and bath filler course.

Tubs have the overflow "opening" so you're going to HAVE to install the overflow pipe.

You will probably need two people to get the tub in place, even if it is fiberglass.

But, yes, you need to run the drain and water lines before putting the tub in place. Caulking is also useful before placement.

In addition to the other answers,if you get a fiberglass tub fill it with water before you caulk.The tub will get a LITTLE bigger when its full.Which can cause small cracks in the caulk if caulked empty

here goes am a plumber and u can do this your way but if it over flows and causes damage to your home the insurancece does not have to pay for any damage done by leaving the over flow on hooked this is why they have codes for the insurancece companys are all behind the codes and this saves lives too.

wasnt aware of bathtubs that are totally black, w/o hole cut i guess.

but you can get a solid cover for the overflow making it non existant

i dont know anyting about bathtub installation sorry