A lot to unpack here lol. I'll do my best. Just to clarify ahead of time Nosy already has the whole game planned out including some NG+ stuff. The times that Liz is with MC and you dont get any nanobot stuff is most likely Nosy's decision so far, maybe this will change down the line.
If you forget to give her the ring we currently haven't hit another point to give it to her at a different time. There will be a point in a future update I believe.
You'll get to a point in an update after 0.12 where she says that they can go without the use of condoms, I'll keep this sorta vague to avoid spoilers.
Doing something like that with the location app would require significant rework of the location app and how it currently is is probably how Nosy has it planned. Maybe he will upgrade it down the line.
Can't remember if 0.12 has the addition of the x-ray function so I'll avoid anymore spoilers than that with this topic.
The topic of Sam has been discussed heavily in patreon chat. Nothing significant has been teased by Nosy as of yet. But stuff with Sam will most likely happen.
As far as antiNTR Nosy has said that ntr will occur on some level for every path, it's in the name of the game.
For L25 it is one you get for hanging out with Liz early in the game. You won't get any notification for it but it will be in your gallery so make sure to check for it there. If i remember correctly it's before the sick days so one of the first days she asks if you want to hang out.