SHORT ANSWER
My answers are of course just my experience, Ysal is of course the best to answer.
- Pills/potions use is bad, probably no tat if you always use them, magical armor is not as bad, can get a tat using it, probably won't get through the religion.
- And keep in mind, with all things, most likely anything is possible, just not always probable. It will revolve around your rp. Maybe you can be the first mage to get tat'd by Ysal. Again, I doubt it, but you never know. Maybe you could.

LONG ANSWER
My follower was an uncaballed exploration driven dwarf pally if that helps you along. He didn't hate magic, just didn't think dwarf's really need it. He had it go in the following.

Pills/potions:
At our first meeting, my character's distaste for magic came out, and so he swore to avoid potions/pills/spells on him. She might not demand it of your character necessarily, but she is a battle imm. She hates magic, and by default all mages, so you can't expect her to want her followers using magic. Perhaps initially you might be able to convince her to let you use them, but as you progress with her, probably expect to go without.

Armor:
Gray area, this will be more heavily driven by your rp with her. My char did in fact get tat'd. And he wore magical armor up until that point. But again, battle imm, hates magic. So she pretty much told me if I ever wanted to go further in her religion I had to avoid all magic, including armor. For Rp reasons I went straight to Tahren, sacced it all, never wore any again, and made up for my errors by saccing everything magical I saw to Tahren. Essentially was a quasi-rager in terms of thickening the veil, but at no point did ysal ever tell me to run around and kill all mages. Religions are not the cabals, and characters will differ. There is a divide between a battle imm speaking to a rager and to a follower. Cross over probably, but not 100%.

Rp-wise:
She is an ideal religion for a rager since they have magic restrictions anyway, but she is viable even for non-ragers. Though as any empowered class prayers make you die a hell of a lot less than any other class probably will. Proably would say for a non-rager, use one of the 4 empowereds, unless you really don't mind dying a lot, especially in pk. For example, hard to survive a prepped summoner when you have to flee by foot if it goes bad, have no magical preps to aid you and have no rager powers helping you in the actual fight. You can do it of course, but it'll take a thick skin to deal with the inevitable deaths that will come from forgoing magic.

Hope I don't turn you off to her with this info. My char age died with her, so trust me, the rp doesn't get old if you are into it and can let the bad things slide by. You might find (as I did) her no magic trend makes you rp more and creates lots more chances for it than you might think. Hell, I know I'd be curious to know someone's story about hating magic, and not being a rager.

Thanks for the info, think you saved me some hours of frustration. Probably try her religion with a true rager, since giving up all magic as a non-rager wouldn't be fun for me. What's interesting though is magic really isn't forbidden in the games dwarven culture. I mean I know they no longer study it directly, but there are plenty of magic dwarven runes in the game and I believe ludan carries a magic ring and the mark of the dwarven crusader, etc.

That which does not kill us,
makes us stronger.

No problem. Again, you don't have to give it all up, it would be rp driven. My char was the first to get to a few points in her religious path, which is why he forewent all magic. Yours you could take as far as you wanted, and so might be able to use magic to a small extent.

And yes, Ludan's ring is magical. Mark of the dwarven crusader is not. Blessed things are not magic, big difference. I.e., can use a healer, those are prayers, which arguably you could say all stem from ysal, and so are alright fer her followers to use.

But have fun with it, hope you enjoy the char as much as I did mine.