Need advice on finishing a basement?

I would advise a dropped ceiling then you won't be locked out of access to the upstairs floor and walls if you ever need to add a receptacle or anything like that in an upstairs wall.

Waterproof the block wall first then frame a regular 2x 4 wall at the block wall. Use blue board insulation and screw paneling to the studs for easy access later if needed. This will allow you to nail up regular boxes for power and phone and give you more room for insulating the outside walls.

I would use normal 2X4 studs and not metal ones.. First I would paint the internal concrete walls with epoxy paint mixture to seal out any condensation seeping through. The bottom plate can be fastened to the concrete floor with a red-head gun. predrill the studs for any electrical wiring or pvc water piping. Be sure you can tie-in to the sewer and water system.I would use the fiberglass insulation even though the 3 walls are underground. It makes for quieter sound in the room. I would not use drywall but would use paneling over the stud walls. The ceiling can be an insulated fiber tile system that will support overhead lights. Floor can be indoor-out door carpet. or carpet tiles, both are easy to install and do not cost too much.. Good luck.

My suggestions are to use a mocha type color for the wall and even the ceiling. Hot Cocoa sw6047 Tan Bark sw6061 (favorite) Mocha sw6067 What ever your choice is I would paint your trim a few shades lighter. For example: Wall color - Tanbark sw6061 Trim color - Interface Tan sw6059 or Likeable Sand sw6058 All these colors are from Sherwin Williams. I suggest painting your ceiling the same color of your walls forthe simple fact that it's a theater room. Also, I wouldn't use a very glossy paint; maybe an eggshell. A sectional is a good choice maybe a redish or maroonish color.

we normally just nail firring strips to the wall and nail drywall to it much cheaper and less work .if you want to insulate use ridged foam boards and put them between the firring strips..done it more times than i care to count in the last 50 years