Your guide was extremely helpful, thanks! You said you don't know how things work in Oasis Landing, but I think I can answer some of those:
1) There will be generic sims later on, but whether they'll move in houses or just be homeless townies, I haven't yet tested that long.
2) Time in OL starts when you first land your feet there, so if you go there later, you'll have a good chance of snatching 100% unique spouses for at least one or two later generations.
3) When some of your sims go to OL, but not all, the ones left behind do not age. I have no idea is this kind of thing banned, check yourself, but if it isn't, it's an easy method of freeing up precious household space. Beware: can cause broken family trees.
4) If you spend a long time without going to future, you'll need to know that townies there do age while you're away. So, don't be surprised if you end up with a bunch of elders in futuristic clothes.
All of these tested by myself, but my game is buggy and my computer old, so some may be caused by bugs and/or glitches.