If Universal doesn't reopen until June or even later, then it might not seem prudent to start HHN in early September, especially if attendance is trickling in.
Universal could not open for regular guests until November, I'd still expect to see HHN in September. If anything, this year will be a throwback to the 00s, when the locals-driven Halloween event kept the lights on in the park during the day the rest of the year.
In general, as soon as this blows over I expect everything in Orlando to be very locals oriented until at least October 2021 (WDW's 50th). Deals and events designed to get locals to come back. That means a huge push for HHN, whatever the content is.