1×8 retro mod

Hi there!

I am building a old retro race bike from the 70's. But theres a thing i cant get figured out.

I want to make a 1×8 setup. 8 speed in the rear as its a Campagnolo 8 speed hub i would like to keep using 8 speed. I would like to fit a 1×8 hollowtech crank but cant seem to find any only 1×10.

Now i found out there is a new Shimano essa series 1×8. This is with a square bb. Ive got ita threads. Now the question. What bb will fit this cause i cant figure out all the differences in bottombrackets. And will this work?

Thanks in advance!!