You're seriously going to say that Univision didn't have unique aspects as compared to iHeart or Cumulus? Even with that, the approval involved a small fraction of the broadcast outlets being requested in these other cases. I'll take your response as you have no citation on a scale of what Cumulus or iHeart is requesting. You couldn't, because such an approval has never been considered.
Univision is an American company... going back to being owned by Hallmark Cards, and then a public corporation up until it went private earlier in this century.
To the FCC, Univision is no different that iHeart, the old CBS that had both radio and TV, and any other broadcaster. There is nothing in the FCC rules that separates Spanish language... or any other language... stations from general market English language stations.
In fact, I am still asking myself how Univision is, as a corporation and licensee, any different from any other group broadcaster. I fail to find any legal difference.
In fact, with radio and TV, nearly all in huge markets, Univision has greater revenue than most of the pure radio companies.
So, other than it being so large, there is absolutely nothing unique or different between Univision and other larger broadcasters.
In FCC "administrative law" (a legal term that even includes a court system with hearings, etc.) uses prior decisions by the Commission as precedent for future decisions, petitions, hearings, etc. There is now ample precedent for foreign ownership, both by foreign citizens resident in the US and foreign corporations based outside the US which are expanding into the US with station ownership.
The fact that the FCC has given 100% foreign ownership authorizations at all is precedent. There is absolutely no reason to think that this is not a blanket policy now, with the only difference being that each one needs a specific waiver grant. But each sale requires FCC approval anyway, so there is no change.