I loved when we was getting a character roughly every 2 months between and . Felt like the right amount of time for me personally.Its worth noting that the time between Min Min and Steve is longer than of the times between characters of the first fighters pass, which were often much shorter. I think the big factor in regards to time will be how complicated each fighter will be here on out.
The lengthy gaps in FP2 is probably a mix of COVID and the first 2 characters being amongst the least conventional in Smash history. Maybe they front loaded the pass with the complicated characters to account for potential delays, things might speed up to FP1 levels later on.