Thank goodness you have reached the owners!
So happy they are going ahead with the desexing Skye, if she is in season or heading into that phase she is engorged with blood and her uterus far more
fragile for surgery, so be sure to let the vet know.
They will probably give her fluids throughout surgery and after, perhaps some pain relief too.
Perhaps they can lop off the busy bits of the male too and make it a double appointment!
The little girl will be still under the effects of the anaesthetic, quite low and groggy after her surgery if you pick her up the same day, though she will pick up quickly during the next day or so. If you are concerned re care I would overnight her with the vet until the following morning.
If you decide to bring her home the same day bring her inside and keep her comfy in a fresh bed and make sure she has water. She will be thirsty during recovery and then let her sleep it off.
If she is up to it and interested feed her a small amount of a healthy simple dinner a little later.
Take her out for a wee on the lead close by when you get home with the lights on and then back to bed.
The vet will explain everything to you though check her stiches daily and make sure they are clean, dry and of good colour. If you see any redness, swelling, fluid or sticky junk hanging about give them a call.
Her stiches will need to be removed within 7-10 days and the vet/nurse will do this for you.
RE the male he is probably all fired up, full of antics and showing off BUT you need to be safe in working with him.
Is his tail wagging or is it straight up in the air?
Is he leaning forward and up on his toes or is he fairly relaxed in his body language?
If he is showing signs of aggression...Tail up, leaning forward and on his toes then you need someone with you when handling him.