The lowest level to do the HT prequest is level 80 -- by then, you should have maxed crash anyways. You can level urself to 129 and advance if you want the benefit of Stance but it's not necessary
Having stance will improve your total damage dealt because you'll waste less time repositioning the crash mule. Every second you spend controlling the mule is lost DPS. If you run HT on a daily basis, I think most veteran players will recommend you to get stance. That being said, if you can't afford to leech to 129 (not 130), then you make do without it!
I mean is there a amount of STR required for 3rd job or 2nd job? For example, we need 35 STR to pass 1st job advancement
nope you can add Pure HP and do fine with 35STR. I'd suggest you add STR to lvl50 though so you can enjoy CPQ1 & CPQ2 content instead of buying leech. Then add HP afterwards, you will have enough HP to go around easily since warrior's HP gain is pretty OP
Jooon is right about the STR ti enjoy cpq1. but i did it and i regret it cuz u should go blood wash(adding all the ap to HP) so u can save money on pots. each HT can cost 1000-1200 potions. and if u above 20k HP u can use elixer rather than power elixer, will save u like 6-8m each run. in the long run its a lot