Question Time, guess work?

[x.l.r.8]

Ok, i have a few new questions.
to start with we have a new mouth to feed so I need to get her on the straight and narrow, her story is sad and she coems to me at 1 year old (approx, still has shiny white teeth) and is a cross of something (chow chow and something smaller like basset hound or dauchound?, yes picture will follow , she is under weight by a good amount, I estimate her at 30lbs and for the sake of feeding extra I made it 15 kgs and I'm going with 3% rounded it up to 500 grams (because thats what I packaged the pork in for Riley) Riley has extra's like herring today to make up the 750 grams he needs (he's putting on weight nicely now, he finally has some meat on his ribs and when he lies down you have to look hard to see any bone through his short hair) I jsut need to get food into Missy so I'm going to do what ever I need to get started, lighly seared and chopped into 4 bits and she inhailed it, not interested in chicked necks other than licking them, but we have time to introduce more once I am happy with some weight gain, she has long fur like a chow but when you stroke her it's like running your fingers over a xylophone, and thats through the thick fur We also noticed tonight she has worms and she also needs spaying,
so to the questions?
1) I know this is the wrong place but will I have to retreat Riley?,
2) How do you estimate the desired weight of a dog who you have no idea what they are meant to be, like in mutts? (we don't know this dog so i guess I have to overfeed and back off is she starts getting overweight)
3) With worms will she still put weight on? (there the white tiny flat ones)
4) Initally would you feed both dogs seperate? (she is crate trained so I was going to put her in the crate while Riley has his 10 minutes to do his stuff, then hold Riley while she has her fill as she will need longer to adjust to having to chew once she starts on the bony stuff)
Were off to the vets tomorrow to start on some of the issues but I was hoping for some advice on issues she will not be able to cover.