Yes, you have to take the same stats you already have, and stretch it across a greater number of people.
That lowers the rate.
Heck no, that’s part and parcel to how crime stats have always worked.
We’ve always known we only get part of the picture; it doesn’t hide the details we can clearly parse out.
We know for instance that urban blacks commit more crime, at 4x the rate than whites, and which is disproportionately committed against themselves. That wasn’t hidden at all. This despite being in a population whose report rate is lower than it is for any other race.
Hispanics meanwhile are following the same domestication trend of the Irish; who were more violent when they first showed up, but decreased as time went on.
Back in the 80’s they were nigh-equal to blacks, today, they’re half of blacks, and still falling.
Long term trends. It’s the bane to your entire argument. You act as if they don’t apply in sociology, as if the short term trends are all there is.
You’re also acting as if the Hispanic are developing the same way as the Urban blacks, when nothing shows that. The Irish or Italians are a far better comparison, to include the part where they give up their racial identity and start identifying as white.