It sounds as though the 20 mil may be the way to go because of ease of installation. Although the 28 mil liners at Pool Warehouse are the same price as the 20 mil. Is a 28 that much harder to install without wrinkles?

waste - I believe the bottom is cement/vermiculite but wont know for sure until pulling the old liner.

I have 6 to 9 french drains that are capped around the pool so will need to rent a trash pump for drainage.

After thinking about it I probably wont mess with putting steps in unless it can be done without much expense. Don't want to buy any kits was thinking more on the lines of doing some concrete work inside the pool myself while the old liner was out.

Attachment bead.... It looks like the liner is tucked into in a slot above the water line and has some push in beading. At the top of the slot is a 1" to 1 1/2" plastic strip that appears to be glued/cemented to the foundation wall. I can take pictures of the pool at some point and post them.