Very sad to hear about Emma. Are the vets and specialist absolutly certain it's not Ectopic ureter? I would look at doing a contrast scan to rule it out completely. I only say this cause all of Emma's symptoms are identical to what my Lab Kona had. She would dribble constantly and never even realize it. She will still let us know she needed to go pee and would squat and urinate no problem but anytime she had anything in that bladder it was dribbling out. I had to laugh about checking her butt but if I was to add it up I probably have months of time spent wiping her bum and legs and also putting cream around her privates due to the urine causing bumps and infections.
The UTI is very common cause she is leaking urine. It's difficult to keep that area clean and prone to infection even more now. A diaper with a maxi pad inside it will help a lot since it will soak up the urine and help keep her dry. I know when we first got Kona we battled a few UTI's and when the UTI's never went away that's when the vet recommended we see a specialist. But before the specialist we did like you and tried every medicine and option under the sun. I easily spent 4-500 on medicines and different options. None of them made a difference except give her more energy. The only way to rule out Ectopic ureter is to have a contrast scan performed. They will inject the bladder with a dye and do an xray and make sure the ureters from the kidneys are working correctly and going where they need to go.
The retriever breeds are more prone to Ectopic ureter and females even more so. We ended up having one done and found out that both of her ureters went into the bladder but then came right back out and dumped into her urethra. So since being born her bladder was never used, never had a chance to develop.
Anyways, I don't need to go into my story. It's incredibly long, lots of surgery's but has a very happy ending. If you want to hear it all and what we went through I would be happy to tell it, just don't want to write a novel in your thread.
Let me know if I can offer any assistance. I have been through what you are going through and it's rough.
Anyways, I know it's more money but I still would want to rule out Ectopic ureter. If she does have that it can be cured or improved greatly.
Oh and just to make you feel better. A pic of her wearing the diaper of shame....(poor girl, it's not her fault.)