Looking good! I like the layout and it flows really well. Bathroom, storage, and utilities are all in good spots as well, not interrupting any open spaces you've laid out.
As much as we love having a spare bedroom in our basement, I do wish we would have explored creative ways to keep the space open while still creating an area for sleeping. There's so much flexibility with an open space so it can serve multiple purposes, like the office/sleeping space that you're looking for. And if you ever reach the stage of absolutely needing another bedroom, I can think of worse projects around the house.
In all my research more lights is always better, and you've done a good job of that, I don't see it being an issue. I went a little overboard as far as outlets go, but I haven't regretted that decision at all. It's really nice to have the extra outlets around the basement. So definitely error on the side of more outlets as well.
One thing I regret is not thinking about wall sconces/light features enough. We have three total in our basement, but I would have liked a couple more. Really think about that as well.
As far as your questions go, I didn't put low voltage wiring in my diagram so you should be fine there. Consider running Cat 6 instead of Cat 5 just to future-proof your network, but this wasn't a deal-breaker for me with WiFi. I'd be completely happy with 24" OC studs, I lost no sturdiness in the few areas where I went with this method. Where you'll be mounting your projector and any other equipment be sure you reinforce those areas with extra studs. Also be sure you give yourself plenty of studs/plates to mount your equipment to, more is always better 🙂 You never know if your plans will slightly change so always nice to have more options when it comes to mounting.
Everything else sounds great! Looks like you've got a good plan in place and honestly a good plan will cut back on both time and mistakes. Best of luck and keep posting here with questions as you go through your basement finish!