Looking at he first picture of the rolling chassis I wouldn't recommend nor use that frame
The main reason is the lack of cross frame stiffeners and the lack of a frame beyond the rear end mounts and into the rear of the unibody
On your deal I think it would be much smarter and easier to take the car to a good well known chassis builder and have them build the chassis and roll bar or roll cage to your needs Please let us know what you do and the results after you get the car done