I think the short answer is he's ages away. The Cell event is probably going to release in the next two weeks or so, because we need to have both the Piccolo Strike and one more before the Event can start (they're units that have the Regen-cancel ability.)
I'm also not hurting for money so I haven't tried the 2nd Hercule stage higher than Normal yet, but it seems they're trying to make the Zeni tiles the main way to gain cash this time, whereas before it was beating the easy mobs and the ? tiles. I've got 20mil though so I'm not rushing to farm it.
Yeah I'd be surprised if we saw him until later in the year and as for Cell, well until we see the banner pop up for it the event won't probably start for two weeks from them so we another month maybe is my guess if we go by the whole Broly thing.
I tested it and yeah basically it amounted to getting the worse on the previous stage Zeni wise.