I'd also recommend to try your best to not AB test any technical SEO data like indexing, schema microdata, canonicals or hreflangs.
Google's link juice usually takes about 5-30 days to fully reflect any technical changes.
My understanding is this is true for keywords as well, but keywords are useful to AB test IMO. This will help determine what searches match your page on google while the technical SEO helps with ensuring you are top ranked on any page result / shown in any rich result.
Obviously, do your own research 🙂