Let's start some discussion...
PSO <-connection-> Classics
Now.. this is something I like to speculate about, since PSO is so distanced from the originals, a feeble connection at least plot-wise would be nice.
Sadly Sonic Team seemed to want to distance the game as much as possible, they did leave a few possibilities open though (AFAIK).
The URAENDING trick, allows you to see a force(=esper)-like character using a spell on the Dark Falz column.

If what I read is right, then the wand the character is wielding is the Psycho Wand, which exists as a weapon in-game as well.
Now, I think it was in
http://www.camineet.net/ that I read about the theory of this esper/force being the 5th gen Lutz from PS4 (Rune) or possible another gen Lutz.
Maybe after learning about the ships that escaped Parma in PS4 (Rika reads some info on a computer at some point) and after the events of PS4 finish. Rune and/or his descendants might have gone on a quest in outer space to seal away all the Dark Falzes that could still be on board of the Parma ships. (assuming there were multiple Falzes)
Furthermore, DF in PSO is sealed with the Algo spell "MUTTS DITTS POUM", indicating that whoever sealed him knew that Algo is a seal of the darkness.
Additions? Corrections?
I'd like to develop this further, but maybe there just isn't enough information to link the two..