"Fatman, YOU GOON, how could they do a triple reveal?"
Well, like I established, they could do some in the Direct and some for 5's showcase that, like Banjo, would probably be immediately afterwards. As others have pointed out, Amiibos releases and character releases are one of the most consistent patterns we have so it heavily suggests a shadow drop. Well, poo, the Fighter's Pass is done...But wait, there's more! They'd probably want to immediately show off the first character of Season 2 but, per rumors, if 6 is supposedly a bonus character/pack, that then makes 7 the start of Season 2.
What makes me think 6 would be shown after 5? Well, precedent of course! After Ken and Inceniroar were shown off, then came Plant, the in-between of the base roster and Season 1. The Fighter's Pass was then announced but with no characters BUT Nintendo already announced Season 2 back in September, meaning there's no need to repeat that it exists and to just go ahead and announce the start of Season 2! This is particularly on to note because the decision to have Joker shown at the VGAs was supposedly decided really late, if I recall correctly, as late as October 2018. This potentially establishes that Joker COULD have been announced in the November Direct but they held it off for the sheer promotional value of metaphorically surprise assblasting everyone at the VGAs. Again, this precedent no longer exists.
Another thing to consider is that, following past precedent, the first Season 2 character would be released by E3, ergo, they would need to be announced and released before then. Plant was announced in November and released in February, right on the nose. Joker was announced in December and released in April. What does this suggest? Perhaps it suggests 6 being released in February and 7 in April. Nintendo has already announced that another Splatoon 2 update was coming in April so it seems like a good fit, especially if another Amiibo wave is announced for that time frame. In that sense, it would simply be repeating the schedule of last year, likely setting things up for a double reveal in E3 and then reveals in the fall and winter respectively.
Here's an outlook of that hypothetical schedule:
January (5) (Direct, 5, 6, and 7 announced) -February (6) - April (7) - E3 2020 (8 and 9 announced) -July (8)- September (9) - September or October Direct (10 announced)- November (10) - VGA/December/January Direct (11)- January/February 2021 (11).
