Haynes guide says Front minimum thickness: 0.118 inch. Disc thickness new: 1.023 in. and wear limit: 0.905 in.
I had no easy way to measure so I went ahead and replaced, because they squealed, I wanted to try cross drilled, and I was in the mood to do it myself.
About the ABS, it's an item that seems like it should have been a recall (especially judging from the number of posts that were on this site a few years back) There are a number of things you can try, including a dude that re-solders them, cleaning the connections to the brakes, or using black electrical tape to cover the light. [yes that was one of the posts] But I recommend biting the bullet and replacing the module. I don't know if it's still $400 or not, but it's a good case for a once and for all solution.
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'97 855na, Mobil 1, K&N, various IPD's and eBay's