1)leave them alone and build around them
2)close shut off valves and take heater lines loose, drain into buckets and floor and cap off, or take the heater lines loose at the shut off valves
a couple bolts should hold them to the floor, also don't forget the power wires to the heater, they need to be removed or at least taped up
You will be draining out Anti-freeze which can be deadly to animals and slippery as can be, it WILL NOT evaporate so what ever gets wet will stay wet
Our build La Tortuga
Accept the challenges so that you can feel the exhilaration of victory.
George S. Patton