There is some air gap between the liner and the wall in a few areas. Other areas the liner is pretty tight against the wall. If I continue to fill, won't the water just push the liner against the wall in the areas where there is air?

It's not much air, maybe a couple inches between the liner and the wall, most of it near the water level. Oh, and no wrinkles anywhere. We managed to do a very good job of stretching/removing wrinkles with the hot sun and shop vac during the day today. Liner went in around noon and has been baking in the sun all day long.