With the official announcement of more fighters coming beyond the Fighters Pass pretty much gives the green light for the remainder of the top requested characters of possibly being added to the roster. Now, some things to note that may help narrow down the pool of characters that might be joining. During Sakurai's video, post-Direct, when he spoke about the development of more dlc fighters, he mentioned that he saw the inclusion of more fighters as the inclusion of more worlds. The wording there seems to refer to the possibility that the other dlc fighters post-Pass might as well be more 3rd party characters, or 1st party characters from franchises that still haven't been represented in the game. Pretty much the likes of Dante, Doom Slayer, Ryu Hayabusa, Heihachi Mishima, Lloyd Irving, KOS-MOS, Klonoa, Valkyrie, Sora, etc., etc., still have good chances of making the cut.
Another thing that came to mind after this announcement, was the WoL datamine that revealed that there were still unused character slots (after this Pass, there should still be 10 left). Depending on the development of the additional dlc fighters, we could get either:
a. If additional DLC fighters will be released without additional content (stages, music), the release schedule could span the remainder of the year 2020, with the release of monthly characters which would fill out the unused WoL character slots. Presuming DLC fighter #5 of the current pass releases sometime late January, or early February, the additional DLC fighters would cover the remaining 10 months of the year.
b. If additional content is included with the new DLC fighters then, I could see a similar schedule to the current pass (meaning 5 more characters for the remainder of 2020). However, for the sake of following the idea that the WoL slots have to be filled, we could perhaps get DLC all the way through 2021. Though... that... might be expecting toooooooooooooo much.
Regardless, yay for more fighters!