There aren't many of us with FantaSea pools here. I am one of them. I'm in the process of a major rehabbing of my pool--a bit more complicated than yours having a 5.5' deep end. If the local company is not familiar with FantaSeas I'm not sure if their assessment is viable or not. There's a few vital components that must be checked.
1) The base U-channel. It's tough enough and thick enough to tolerate a surprisingly large amount of scale and rust, but too much and the bottom of the pool can bow out. The belly band(s) across the middle under the sane (they will be 16' long on your pool) should also be checked. While down there, be sure the metal is properly bonded (grounded or "earthed").
2) The steel trusses of the super structure that carry the deck and resist the water pressure on the water walls. A couple of people here have had quite expensive repairs with one of the trusses failed, usually an end truss. I found one weak spot in mine and welded in re-inforcing steel before it fails. Also the bolt that hold the side trusses to the end trusses need to be checked. I believe they are Grade 8 or Grade 5. I've forgotten.
3) The "gussets". These are the upright 4x4s with angled 2x4s attached to them that connect the u-channel and upper truss structure. They need to be checked for rot and loose side plates.
4) The Water Walls. These can be 3/4" plastic clad 4x8 sheets of plywood, 4'x4' plastic and aluminum "Space Age Panels" or simply 3/4" 4x8 sheets of pressure treated plywood. Look for rot and deterioration.
5) The copings or "tracks" as you called them, particularly the corners.
You'll find out soon enough if the solar panels leak when you start up the system! (LOL!)
You mentioned a pump but not a filter. You'll need that. What pump did you get?
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