New bike lots of questions

[NZRalphy]

Blue loctite, blue loctite, blue loctite, blue so you can take it apart.
Red sticks it for good.

 

[Blackal]

242 or 243 would suffice.

As above - use a 'low yield' type, and in case you get carried away with the bottle and start using it all over the place - keep it off plastics, as it can tend to destabilise plastics. (weakens the structure).

Ebay can be a good source of small botts of loctite.

 

[Bendy toy]

Slightly OT but it is Loctite. Probably 10 years ago, I bought Loctite 518 anaerobic gasket in a syringe type tube. Its amazing stuff and only just getting to the end of the pack.