I am so sorry about your dog but I will try to help. One bit of optimism is that her creatinine decreased from 8 to 2 in a matter of weeks only on SC fluids and Aluminum Hydroxide. In my experience the creatinine only decreases slightly.
Is it possible to have the abscess removed using a local anesthetic and sedation or even very safe general anesthesia? Whatever the cause of the abscess, it is a sink of inflammation that is impacting your dog's organs and elimination of that inflammation should have a positive impact on your dog's well being; otherwise, your dog may require continuous antibiotic treatment which adversely impacts her gastrointestinal system. Her GI system is already slightly compromised due to chronic pancreatitis. It is a vicious cycle. Has the abscess been tested? Is it just an abscess, or a ruptured sebaceous cyst, or other benign lesion, or is it something else? If it has not been lab tested yet, once it is removed it can be sent for biopsy.
Healing or controlling your dog's gastrointestinal system is also very important because the GI system must work well to process everything being put into it. This includes all the oral medications. A Chinese herbal formula called Eight Gentleman is very good for healing the GI system. Additionally, due to all the antibiotics your dog has been on it is essential for her to take a good probiotic, such as Fortiflora, which is available from your veterinarian. Eight Gentleman is available online at multiple sites. Her dose would be a full human dose and frequency, but I would begin with a small dose and titrate up due to GI issues.
For the kidney issues try adding Azodyl (available from your vet), and Rehmannia Eight (available online) at same dose as a human. As with all medications, begin with a small dose and titrate up.
Please post again after going to the internal medicine specialist and to ask questions. I can give more recommendations once I have more information. Thank you and good luck with your dog!