You are putting radiant heat (PEX) directly in the floor. As such I don't see any advantage to putting the plumbing PEX in a sleeve, and the disadvantages are being pointed out by other answers. If you are particularly paranoid about the plumbing for some reason, run double lines to everything and cap one of them at both ends to serve as a spare. In addition, you can wrap and tape sill seal around all the pipes at any point where there will be an expansion joint (it cushions the pipe just a bit if the concrete cracks and moves), and toss in a bit more reinforcing steel than the bare minimum that will be specified.
Wrap the sill seal around the pipe for about two feet (one foot either side) of planned expansion joints.