I'm a postdoc in philosophy, rather than English, but I have applied to a bunch of positions advertised in the summer, some of which have been TT. (Don't know much about HBCUs though, sorry!)
My experience has been that there is no real rhyme or reason to summer hires. The ordinary process (first round interview, on campus interview, offer) might apply or might not. For one years, they have tended to do just one round of interviews, usually via Skype, and then make an offer. For summer TT hires, they might skip the first round and just bring three or four people to campus.
My sense is that mid-July is the latest an offer could go out for a TT position starting in September, not because the University doesn't want to stress out their candidates (they don't care about that), but just because there are lots of compliance issues and paperwork that needs to be done before the start of class, such as criminal background checks. Working backwards, that would yield a timeline like:
- 15 July, offer goes out.
- 10 July, search committee meets, makes recommendation to dean/provost.
- 7-9 July, interviews conducted.
- 1-5 July, first round interviews conducted, if there were any.
I think that would be an incredibly tight timeline, so I would take it that if you haven't heard any good news early next week, then you've probably not been selected to move on.