I've never consumed xantham gum since going keto. You absolutely don't need it. If you want it, find it with the Bob's Red Mill stuff (almond flour area).

I wouldn't put olive oil in coffee, if that's what you're saying. But, it's fine elsewhere. I wouldn't cook with it, use it cold. Coconut oil is good in coffee. You don't absolutely need grass-fed butter. In times of trouble, grocery butter comes to me, whispering words of wisdom, "just use me." Truth be told though, I usually just add heavy whipping cream into my coffee instead of butter or coconut oil. Cream has more carbs, but not a significant amount unless you're using a ton of it.

Vitamins and supplements: I use none. But, until you're adapted (and some would say even after), you should up your sodium, magnesium, and potassium intake. Eat more salt, add a magnesium tablet to your morning routine, and maybe use some "Lite-Salt" which has potassium instead of sodium. That will help keep your electrolytes balanced. In the early days of adaptation, you're going to be losing a lot of water weight, which will cause a loss in these things as well and can lead to muscle cramps and other unpleasant side effects. I almost never supplement these now (over a year into keto) without issue.

Exercise: Less strenuous than usual (if you're into heavy exercise) until you adapt. After that, whatever you like. You can do none. You can do tons. It's all personal preference. Exercise is generally not part of the diet. It's great for health, it's a wash for weight loss.

Recommendations: Learn to love fatty meats. Add butter to everything. Substitutions rarely satisfy the craving you had and only keep it alive. Giving up trying to replace carb-filled foods with substitutions made my mental life so much easier for keto. That's just me, some people love substitutions.

Small town resident here too. Kerrygold butter is grassfed and is usually found in the deli department.