The title and James's cloning
Here is my interpretation of the title which is very well chosen. An infinity pool is an object usually associated w the rich property playgrounds so there is the reference to the wealthy.
Here I think the real meaning refers to the cloning pool being infinite. These people can keep committing crimes and they just keep cloning, so they have an infinity pool of clones.
I think the real James was killed in the 1st cloning. His calling out to EM for help. the James behind Em breaks out a small smirk as I recall watching the execution too knowing he has taken over for the real James.
He really doesn't seem the same after. The scene where he is spitting olives at another couple while dining seems sociopathic and way out of character for the insecure original James.