You need fire air stop at the top of the wall.
We usually use a 2x8 for the top plate or 2 2x4s side be side tight against the sill on top of the wall.
Your steel beams will transfer the cold so I would plan to bring the wall 2 1/2 out from the posts so they can be wrapped on foam board.
The fire stop is intended to stop air so cutting and fitting around the posts as best you can and spray foam the gaps.
The trick is to figure how far out the wall will come mark that on a ceiling joist in each corner and snap a chalk line across the joists.
Then when you have the fire stop up, plumb down in each corner and mark the floor and snap a line across the floor for the base plate.
Sill gasket if availible is cheap and easy, just staple it to the bottom of the base plate.

Owens Corning FoamSealR 3-1/2 in. x 50 ft. Multi-Use Ridged Sill Plate Gasket-1FS - The Home Depot

 

So should i cut the firestop to fit in between the steel comlumns? None of the contractors ive spoken to have brough up the firestop. Is this specifically code in certain areas or standard. Im in Wisconsin if that helps.

 

It's minimum code.

 

FYI - Wisconsin is the only state not using the IRC but still code even there as memory serves.
Not worried about moisture coming through the walls? If you are maybe dimpled drainage mat then foam. Fill the depth of steel beam with foam, then offset the sheets with a 1/2" thick foam over all of it like Neal said. Add in your flooring panels then stand your new walls & have fun (if water is / might be an issue - hope you have a sump pump also) - if not then you can stand walls & then do floor

 

Thanks again for the replies. Unfortunately this project was put on hold for quite a while but am picking it back up now.

Decisions I've made thus far..

Will be using this sub floor DRICORE® R+ 1" x 23-1/4" x 23-1/4" Insulated Subfloor Panel at Menards®

and will build the walls on top of the sub floor.

will be using this foam for the walls R-10 (15 psi) Owens Corning® FOAMULAR® 150 Extruded Polystyrene Foam Board Insulation 2" x 4' x 8'- Scored Square Edge at Menards®
glued to the concrete and each other with foam board adhesive.

The steel support beams on my walls are 4 inches deep so I was planning on putting 2 layers of the 2inch foam between them, then another contiguous wall of the 2 inch foam on top of that then building my wall frame in front of that. (Let me know if this sounds sensible)

Regarding the firestop would the board go on top of the foam board or the foam board goes all the way to the joists and then the board butts up to that? Or should board go right up to the sill and then the foam board up to the fireblock board?

What about vertical fireblock. I've read you need that every ten feet. Would that have to go all the way to the concrete wall and create breaks in my foam board insulation?

Last thing on my mind at the moment is I'm going to have to redo the stairs as well. From what I've read so far I think I can have the stair land onto the dri core boards. Does this sound like a bad idea? Or should it land onto the concrete. (My main concern is to keep the wood from soaking up moisture from the concrete and not creating a break in my subfloor). Probably not too critical as im leaning toward creating an L shape with the stairs and will have a landing at the turn but best to get some ideas.

Thanks again!