I would get a full immune work up from an infectious disease specialist or even your primary care, just make sure they check all the sub classes of the IG stuff. Sorry that is not scientific sounding. I am basing this mostly on the throat ulcer comment, though if you were already on asthma meds, it could have been thrush.
Allergies, asthma, eczema, sinusitis, ear and upper respiratory bacterial infections often all go together. That explains about half of what you listed and exists in people with and without CF.
Changing stools is normal as far as I can tell. People here speak of violent gastro symptoms and being underweight before diagnosis despite eating a lot of food. Is that what you mean?
With your asthma diagnosis, what was your overall lung function? Were you told it was in the normal range or not? Normal would not rule out lung disease, but below the average range would be telling.
I don't know what crater throat or MVP are.
Plenty of people on this site were diagnosed late and present with atypical symptoms, so genetic testing is not a waste of time. But unless you present with enough big symptoms, you won't get insurance coverage for the testing:
lung damage on x-ray/ct scan, sputum cultures with atypical bacteria, signs of inability to absorb nutrients, sinus polyps.
(Maybe someone else can add something I've missed.)
