The TLDR 2H Barb

Just starting Hell difficulty and strength is too low to upgrade to TU4 weapon. Any advice on how to improve STR around lvl 100 or do I need to use TU3 weapon until I start getting more charms etc ?

You can stick to t3 for level 105 charms, and get stats from there. it is more than enough.

What's used to get high enough AR for hell?
Isn't 1 point into Daedalus worth it or?

Imo no, because it is 5 skill points to get there. Daedalus has base level synergies for life, so 1pt will give you very little life.
This is, you solve ar issue with tu light gauntlets, it was mentioned here many times. Don't look at your ar number and hit chance, with those gloves your real hit chance go up by so much, you don't need to worry about ar. Don't ignore it, but having anyhwere between even 10 and 20k is perfectly fine.

Would like some advice on this one if someone has inputs to the MOs on this weap:

I was considering 5 x maximum damage and 2 x 40 mana on hit?
Jahs in sockets.

Max damage mo is really weak, id debate that AR could be still better value per mo.
Even 5% deadly strike probably beats 30 max damage extra. 5% ds = 5% more total damage basically here.

Quick question, i was playing a summon barb. Assuming I had decent gear what would I want to try for a more end game oriented build? Would deathgaze fill that purpose or is there perhaps something else?

Depends what you want to achieve. This build isn't great at farming, even with some crazy gear, deathgaze coverage just isn't that great for fast clearing places like fauztinville or duncriag.
For bosses, it can get the job done, but again it isn't spectacularly fast. You can build specialized caster at clearing certain boss, and for example kill kabraxis on spawn (cold sorc), just printing those charms.
This build is set up around cheap gear and self found experience, also no respec (which helps a ton for optimizing vs specific ubers). So it is not best or really particularly fast at anything. It is cheap and versatile. It doesn't respond that well to better gear, because skill mechanics limit it at clearing potential.

Actually when I think about it, what this build is really good at, is bremmtown. You can join full game and solo p8 bremmtown with TU gear, and itsn't gonna be even that slow. Crazy exp. Shower of rocks + thunderslam destroys this place.

thanks for the replay. as mentioned before my barb is currently summoner barb so i might go out and look for a few TUS and respec deathgaze. Took a look at the videos in the original post to see how death gaze worked mechanically.

From where is this Stone and what make it?