I do GE repairs almost exclusively and can tell you that I don't see this problem unless fridge is a LOT older than 4 years. Where are the water lines cracking - is it right by the incoming water valve where it makes a sharp turn ?
the suggestion to use copper is a very good one - that is all I use - note that is not part of the refrigerator. The newer GE's use a grey plastic tubing that is superior to the older milky colored tubing. It is the same stuff as PEX tubing which you can get at a plumbing supply store . If the problem is only where it is too close to heat ( compressor ) use aluminum duct tape ( the kind you peel off a backing ) and wrap the tubing in that to deflect the heat.
You have accepted the answer so I don't know where this balance of 11.90 is showwing up . The copper is 1/4 OD and you could replace it . Make a loop or two so you cna pull fridge out and it will " give. Use brass compression nuts and ferrules for the connections. As for as something underneath sheet metal cut exact size as fridge so it doesn't show and hope the floor is level so that it shows up in front if water leak occurs.
They make pans that fit under washers for this but it would not be large enough and it has 4 edges that stick up and would look pretty ugly. As for what brand to go with - you have a good brand now but Whirlpool is also good. they all have their unique problems. People on this site are always saying " I will never buy another Maytag, LG, Samsung, GE, Whirlpool, etc. etc. " See where I'm going ? Once you've had a problem the grass always looks greener - - -