You can use saline eyewash for humans or you can boil water, let it cool and use that. just try and rinse the pee out, then pat dry. A microfiber towel is the most effective type of towel. Is she on oral antibiotics? If she isn’t, it might be good to use triple antibiotic cream on the incision area after drying her.
The incontinence can be due to swelling in the area. Hopefully it will resolve hrself. Urin is sterile when it leaves the body, but it’s a good medium for bacteria to grow in, so it should be cleaned away. Maybe you could use puppy pee pads in her cage for the next week or so. If she pees on a pee pad and sits in it, she won’t get as soaked.
Greens are usually the first food they go back to after a spay/neuter. Pellets is generally the last. I tried to give my Bam sweet treats after his neuter, he’s normally a glutton for anything sweet. But nope, he just wanted greens. Fragrant herbs like parsley, cilantro or mint are often appreciated.