Did you post what the vet's response was to your questions? I didn't see it in today's condo.
Your vet may be very experienced but suggesting that you're second guessing her or you shouldn't be asking questions is not productive. When any medical professional makes a recommendation about a procedure or treatment, they are obligated by law to make sure they have communicated in a way that allows you to understand ALL of the ramifications of their suggestions. It's what's referred to as informed consent. When you take Ella in for her dental, the vet will have you sign paperwork indicating that you understand what the procedure involves and the associated risks. Saying, "Just trust me." is the way people in the medical field get sued, and rightfully so. Even with prescribing a medication, the vet should tell you about the side effects before administering any drug.
The approach I would take is to try to get across to your vet that you want to her to be your partner (and I'd word it that way) in Ella's care. I'd stress that it's important to you to understand her perspective since you value her input. Ultimately, though, it's your decision about what steps are taken to keep Ella healthy and happy. As such, you need to understand all of the implications, good and bad, of what she or the other vet are recommending. In addition, I'd let her know you're going to do your research. Rushing into decisions rarely yields a good outcome, unless the situation is critical. I don't think, from what you've said, that Ella's situation is critical. Further, feeling like you're being pressured does not contribute to your having a good relationship with your vet and it may be worth mentioning that you're feeling pressured.
To the best of my reading, there is no diagnosis of "smoldering pancreas" or "ticking time bomb" syndromes. Some cats do have chronic pancreatitis and are prone to flares. You treat when the cat is symptomatic. There may be some supplements that can help on an ongoing basis but basically, you treat when there are symptoms. Caregivers become attuned to when their cat is "off" and will initiate care before there is a full blown flare. However, if Ella hasn't had pancreatitis and her lab values are fine, there's no way to know what this vet is suggesting. The blood tests that were run for the dental would not involve a test for pancreatitis. Like I said yesterday, using amylase and lipase tests to diagnose pancreatitis in a cat is outdated and wrong. Amylase, in particular, is an unreliable test.
I know you're concerned about the dental. If either of the vets you consulted with thought there was an unreasonable risk with going forward with the dental, they should have told you. Further, if they thought the risk was unreasonable, they should not have scheduled the procedure. If they are suggesting that it's OK to proceed, then it's their judgement that there is no greater than the normal risk for a surgical procedure. You need to understand that there is always a risk when anesthesia is involved. The materials I linked for you about dentals outlines what should be involved in terms of monitoring vital signs during anesthesia in order to keep the risks at a minimum.
It's all of the other stuff that it sounds like they're trying to convince you to do that's creating confusion. And, unless they've given you their recommendations in detail, you do not have sufficient information to make an informed decision. The "Trust me." approach or trying to intimidate with the, "I'm the doctor." routine is (IMHO) a crock. The last medical person who said, "I'm the doctor." to me got an eyeball to eyeball look with my response of, "And I'm paying you so you work for me."
As an example, before I started educating myself on FD, my vet wanted me to continue feeding Gabby prescription food. As I became better informed, I came back to the office with cases of DM and MD. Of course, they were concerned. My vet discussed the value of the prescription food for managing Gabby's diabetes. My response was to ask her if the goal was to have Gabby on a low carb, good quality diet. She said that it was, in fact, her goal. I said "Good." because the the carb counts on the prescription food was between 7 - 13% and it was composed largely of by-products. I also let her know I could buy commercial food (Wellness) that was better quality and lower in carbs. What could she say?
IMHO, if you change several things all at once, you have no idea what's working or what's a problem. If you change one thing, wait and evaluate the outcome, you know if what you've done has helped -- or not. Frankly, the vets should know this. For example, if the vet has you change Ella's diet and puts her on an antibiotic and her allergies go nuts, is it the food or the antibiotic?
Not everyone is willing to stand up to their vet. I'm not saying to get into a screaming match. I'd just encourage you to quietly listen and ask questions and stand your ground. You know Ella. You should not feel like you are being pressured either by us or by your vet. I obviously have strong opinions but whatever you decide, I'll do what I can to help you evaluate the information you've been given and I'll ultimately support whatever decision you make.