You can get tested even though you are on a gluten free diet, through www.enterolab.com
They have stool testing for gluten sensitivity/Celiac, and also for dairy, egg & soy allergies, and also a cheek swab for the gluten sensitivity & Celiac genes.
I've also observed that you seem to be improved just from cleaning out junk from your diet. It is known by many that artificial ingredients in foods can lead to a whole host of issues, including neurological symptoms.
Also, H. Pylori is a significant find and I'm glad you're getting treated for that.
But I still think the improvements you are seeing on a gluten-free, cleaner diet ought to be enough to convince you that the gluten & other artificial ingredients were certainly contributing to, if not completely causing, many of your symptoms.
Again, I recommend the EnteroLab tests (and I have no financial connections with EnteroLab).
I also recommend (again) going to an Integrative or Naturopathic Physician about
your liver issue - that may or many not have anything to do with dietary issues, and an Integrative or Naturopathic Physician may be more capable of figuring out what's going on because they tend to look at people as whole rather than only focusing on one part (such as just the gut), and thus are often more able to find causes and help people more completely.
Oh, and I'd put off the liver biopsy until you can consult with the Integrative/Naturopathic Physician...no sense doing an invasive test if one isn't needed.