Being somewhat active at CrossValidated (and actually a mathematician by training), I would say that:
1. Statistics, as per the scope you outline and per about 98% of the activity at CV, is *not* a subset of math, so no, I would say that this content is already in scope here. (This is of course not to say that statistics in the sense of measure theory, probability etc. are off-topic here.)
Plus: people who have this kind of question will *not* believe they will find an answer at a math site.
2. I absolutely think there is room for a stats site at Codidact, with the scope you outline. (Maybe add topics like forecasting, classification etc.)
FWIW, I will gladly commit to contributing at any such site here.