[ICanHas]

How recent is recent? Is the contractor still in business?

Solution four is extremely labor intensive in configuring the control programming. The labor involved in controls adjustment can far exceed a simple compressor swap-out. A working compressor swap-out is nowhere near as labor intensive as a burn-out replacement.

You may not need an EPA certification, but if semantics are part of the consideration, you may need to be a licensed electrician depending on your jurisdiction.

The very specific example in solution three does not matter if you have an EPA certification or not. The use of non SNAP approved alternate refrigerant in an HCFC or CFC equipment is illegal even if you have a license.

Also, the fairly new system's warranty will likely be voided as turning a system down excessively lowers gas velocity and may lead to oil return issues.

I may have solution 5 to propose depending on your answer to my question which may let you have solution 2 completed quite economically.