I've got a very dry, clean, tidy, high-ceilinged basement in a 4-year
old home, approx 25' X 45' in size. Unpainted concrete block walls.
Poured concrete floor with some minute cracks. The ground outside goes
about 3/4 of the way up. There is no evidence of leakage although
there is a sump pump that I hear turn on briefly every couple of days.

I want to finish off the basement dividing it into 4 rooms: furnace
room, family room, bedroom, bathroom.

Would the following be the best way to start:

1) seal and/or paint the inside block walls.
2) stud out with 2X4s positioned an additional 2" from the wall so
that I could stuff 6" fiberglas insulation between the 16" on center
studs.
3. Cover it all with plastic before screwing on 1/2" drywall

Is this arrangement inviting condensation? Should I maybe delete any
seals and use a de-humidifier instead? Should the bottom 2X4 plate be
pressure-treated? Do I even need insulation... wouldn't the dirt
outside be insulation enough? Is step #1 even needed?

Any tips would be appreciated. Thanks.