Maybe I'm just lazy, but I find it hard to post at a thread with so many questions, so I will just mention some points quickly.
What you think was 1st jhana looks more like what people call
access concentration.
As far as I know the posture matters for concentration and energy practices, but can still be done without and the difference usually is subtle and can only be noticed much later as you progress, and for insight isn't needed.
For now do not think too much about the difference between insight and concentration, it will become clearer as you progress, and just follow the instructions of the meditation you chose.
Sheldon Frith Nicholson:
Its like my sole goal in life is to extract as much information as possible about every subject there is. Its as if I think that if I eventually have enough "knowledge" I will get insight/wisdom.
I also had a lot of problem(and sometimes have again but in a smaller scale) with obsession with information.
The approach that worked the most with me, is:
1 - if you are frequenting some kind of website that contains a lot of "potentially useful information"(like maybe facebook or reddit), I advise stopping completely, or imposing severe restrictions, so after a while "recovering from the addiction" you can realize how stop frequenting it didn't really affect your life and that website was useless after all
2 - if you are having new interests all the time and keep searching information about them, try keeping some sort of to-do list, and when you have some urge to search about something, put it into the list and let it be there for a while, if you still want to know about it and think it's really useful after some days, then it's okay, do it
3 - reading books is fine, as long as you are not jumping around between different books and never finishing one, but trying to read few at a time
Also, I recommend reviewing
this chapter of MCTB