I really think this game will be around Atlantis and aquaman/aqualad centric
I mean we have tempest in the team, aquagirl dies, aqualad discovers black mantas true identity at some point (so I'm guessing it would be during this 5-year gap arc), the shameful departure of ocean master, which I'm guessing aquaman finds out he is his brother, orm
As we know aquaman can team up with u in legacy so that's also could be another hint to be in Atlantis a lot.
A way Tula might have died is from ocean masters trident, which absorbs mystical energy like in the comics, which he used on queen mera, but Tula also possesses some mastery in sorcery and she may have been captured
In season 1, we find out queen mera is with child, but we never here about her in season 2 or the son, which I'm guessing must circulate around this idea abit. In the comics aquaman's son is killed and queen mera leaves him (pretty sure), which could be a reason we also don't hear much about them in invasion.
Just a couple of theories :)
Wha do you guys think?