Hello Rachel. I'm pleased you joined the group, but saddened that you needed to. There's a lot of conditions there and, frankly, I'm fairly amazed Lilah has made it this far. She must be an extraordinary dog. I can only really comment about the kidney disease, as I really don't know enough about the other issues to give advice. The kidney values are bad. I would say the only way of bringing them back into line (quickly) is by having fluid therapy, which you might want to talk to your vet about. I have no doubt the kidneys have deteriorated partly through all the medications she's been on, as there would have been a huge toxin build up from both the metabolising of the drugs and from the by-products of the drugs themselves. If she isn't currently on a canned kidney dog food (such as Hills kd), then she needs to be, as that will help reduce both protein and phosphorus intake. The alternative is to home cook - but that's a decision only you can make. As to whether the time has come, well, again that's a decision only you can make. You know your dog better than anyone else. Is she happy? Is she in any pain? Is she suffering? Is she still enjoying more good days than bad ones? These are things to think about while making a determination.
How long ... it's what everyone asks in these situations, and there's rarely an easy or accurate answer to provide. I doubt more than a year and, if things deteriorate rapidly, maybe only a few months. If I were in your position, I would take it day-by-day and assess on an "as-needs" basis.
I don't know if that's helpful, but one thing's for sure ... you are in my thoughts.
Take care
Tony