Well, if you have a road bike, then some of that MTB stuff is not going to fit. Yours should have side pull caliper brakes for example if you have a road bike. Post a pic of your bike, something is not quite right.

Do you have a hybrid??

Given the drivetrain you are looking to use, the cheapest option IMHO is to just pick up a complete MTB, ready to ride, put some smooth tires on it, and you are set. Mixing components, the lack of clarity of the exact details are both ways to end up spending extra money on stuff that doesn't fit right, isn't compatible with other parts, or whatever.

Even if your bike is cassette, you could have issues, as in 1989, a lot of Cannondales came with UNIGLIDE freehubs (obsolete).

Research first, grab parts later. Parts that come in the form of a complete bike have lower risk, as you know all of those parts play well together.