Installing New IG Liner Questions

My new 20 x 40 Roman pool liner will hopefully be arriving next week which I hope to install with a few friends. I have already emptied the pool and removed the old liner. I have treated a few rust spots and applied thin layer of Hydrolic cement.

When installing the liner, can I use wet/dry vac behind the liner to remove any rinkles ?, if so, does it need to be a certain size (hp/gallons) ? Due to the size of my pool would I need more that one wet dry VAC running concurrently or should I be looking to use something other than wet/dry vac ?

Does it also make sense to replace all the faceplates/gaskets, screws etc during this installation process ?

At what point during the installation process do i need to install the faceplates on the main drain , returns, lights, skimmers and stairs (Vinyl) ?

Yourhelp is appreciated

JJNMRSDAD