Riku will be helping to protect the Portal until, eventually, he will enter the Nexus to return home to his timeline to continue with his canon.

Re-l, too, despite what she's said before...will be heading home with Pino. She has to meet with Vincent again, after all.

Dani will be heading elsewhere, though she'll take her time to protect the Portal and destroy what monsters she can. She can't go home to her universe (as it's been destroyed), but she'll find her way.