Will enjoy following your progress..
I will be updating our liner and surround in the next few years as well. Mines a kidney shape and I'm kicking around infinity style conversion ideas.
Like the water line flush with the surrounding deck idea, not to mention the skimming power of the design.
My yard, like yours is filled with mature trees and pines that love to drop their bounty into the pool.
Good luck and post your challenges along the way!