I am so glad to hear your babies are playing and feeling better.
I hope your vet will agree that if you do choose to feed a commercial food, a food such as Prescription Hills ID Low Fat ( either canned or kibble) or the RC or other equivalent is the diet usually recommended for P.
As for price I pay around $3 a can or $34 per 8 LB bag of kibble at the vet. The Amazon price seems really high. Also 12 cans may be a lot to order at first. She may not like it, and you may decide to convert to kibble. I only fed my dog the canned for a couple of weeks before I weaned him off that and fed the kibble. If you have a Petsmart nearby, as suggested in the above post, they will probably have the food if your vet gives them a script.
I know you are concerned as to what to feed, but in my case I have found the Prescription food is well tolerated by my dog and he keeps really well on it. I feel for him having to eat the same low fat kibble all the time, but he is always hungry and eats it all up every meal. I feed him four times a day and he does well on that regimen. The one issue I have found is that the low fat diet meal seems to be absorbed quickly and he gets hungry again!!
After he was really free of the P and eating just kibble, I started adding about a thumbnail's worth of boiled chicken breast and about a tsp of boiled rice mixed in each meal. These additions seemed to satisfy him better and made me feel I was cooking for him a little. LOL! In my worrywort way, I did retest his P panels and they looked good, so the additions are doing ok for him.
For you it will soon be time to get that bird in the oven
Wishing you a peaceful day with two happy and healthy dogs playing under your feet as they enjoy the lovely cooking aromas in the kitchen.