While it's fun to think what spell lists a SF2 caster may draw from if they were applied, I really hope they stick to SF exclusive spells for the new classes. To help keep the sci fi flavor of these classes, and keep them more distinct from the PF 2 classes, which is a goal they have in mind.
PF2 launched with five casters if I'm not mistaken. Wizard, bard, cleric, druid and sorcerer. And has added a good deal more like witch. For that system, it makes sense to me to have these lists of spells, and then assign one to a new caster class being added, or let them pick one like sorcerer and witch can.
But I'm not sure if that will be as useful or necessary in SF2. It's launching with six classes. One is confirmed to be a caster, and I feel like it's safe to assume one of the other two is probably technomancer or something similar. I doubt there will be three casters at launch. SF1 launched with two casters and ended with four. Only adding two more in the entire life of the edition.
I'm hoping that with the cross compatibility, they'll let people bring their wizards, bards, clerics etc from PF2 into SF2 easily, but have all new spells for the SF casters to distinguish them, and keep that sci fi flavor in their spells. Unless SF 2 ends up adding a lot more casters than SF1 did, I don't feel like they need create spell lists in the same way, and could just give the few SF casters their own spell lists again. Or use more loose category tags.
Or if they do want to have lists or tags for spells, make new ones for SF. Like Tech for spells that interact directly with technological devices, temporal for spells that manipulate time, etc.
We may get some insight into their current plans when we see info on the Mystic. But I'm really hoping their approach isn't to say, just give Mystic the Divine spell list and Technomancer the arcane spell list, sprinkle in a handful of new spells, and then call it a day.