A few questions after getting more into the game
By - Vitrebreaker
Ok first, something to note is the handsome collection has been on lots of sales. I remember I got it I for 5 bucks. You can go to G2A and get it for 10 bucks, some people have moral issues with it but at the end of the day gear box has made so much off of it and has bl3 now, I think it is fine, and so much more than worth it. Personally I am 1.5k hours deep in the game and I will confess I have never made it to op 8/10 solo.
As for DLCs you can kind of do them when ever. In TVHM what ever level you are when you enter them is what level they will be, so if you want to play one enter it, but playthrough it before doing to much else so you don't get over leveled.
When you do them is not too critical. I would say to do 1 or 2 of them now in TVHM and then when you hit 50 head into UVHM and do the rest. at that point they will scale to your level and it will be fine, but be wear that Tina's assault on dragon keep might be hard on UVHM till you get used to the difficulty.
GTG but i will try to answer the rest of your questions in a bit
Actually, that's already usefull, thanks !
For elemental weapons I would just say not to worry too much about it. Having the right element for your enemies does help and it is important, but especially for TVHM it is not critical, and just using the best stuff you find can probably get you through.
If you just need an elemental weapon for a mission that requires it (like setting varkids on fire) I would recommend going to the gun vendors in marcus' shop in sanctuary and checking the vendor and marcus (he is also a vendor) for one and then save quitting if you don't get it.
When you get to UVHM enemy levels will scale you, so you can find legendary weapons you like and farm a new one, I would look into a few of these. Maggie, Lyuda, Unkempt harrold, Badaboom, striker, fast ball, storm front, the list goes on, but these are all strong. Just farm a new one every 2-4 levels.
I have personally never played sal, but I know he is a character who definitely has wrong ways of playing him. If your build is working and fun keep it up. If it is hard to keep up, or if you hit a wall in UVHM I know the strongest build is to go into gun lust and get to money shot. It is often considered the most broken skill in the game. You can use it with shot guns or pistols to great effect.
What your doing is fine but a little unnecessary. I would avoid taking missions with blue rewards in UVHM, actually I would recommend checking the wiki to see if they have a unique rewards and if not go for it. You can the do these when you hit max level and you will have good versions of all of the weapons. in TVHM it doesn't matter as much. I recomend just doing them and trying out the weapons to see if you like them and then you can know which ones to save till max level in UVHM.
This isn't really something you need to worry about. It matters a bit more for krieg and Maya but you are never going to need to make a new character or anything because you didn't save a mission.
Even if you do a mission to early and you want to get it again you can reset UVHM. It resets all the missions and everything. Like a new playthrough. It is a lot, but it means you can get it all again.
feel free to ask more questions if you are curious
About the fire weapon: Did you need one to burn varkids? In that caseat the start of the map there is a snowman near the vendor stations and the first time you shoot its head you find a blue unique fire pistol (same one captain flynt usally drops).
Othewise you can give moxxi tips. After some tries she gives a weapon. The first weapon is a certain unique corossive smg but afterwards she will give a certain unique fire smg. Keep in mind that you can only get that corrosive smg once per character (not just difficulty like quest weapons). So if you want the corrosive one on highest level you may never tip moxxi.
About level 50 weapon mission rewards: This is called playthrough 2.5 (still on second playthrough with everything upped to level 50).
Play those mission on normal and check out the weapons. If you like them then try to postpone their quests.
But do not worry to much about it. The DLCs add Ultimate Vault Hunter Mode (UVHM), which increases the max level to 72 and has 8 Overpower levels (OP1 to OP8) and that makes level 50 weapons obsolete anyway. The latest DLC - which is not included in the Handsome collection! - increases this to level 80 plus OP10. You can reset the story in UVHM which allows you to fetch quest rewards multiple times (at the cost of starting the story from the beginning ... ).
OP levels: simply said enemies overlevel you by that OP level but they also drop items with that scaled OP level (and "only" require your max char level). They can be unlocked once you are max level and each new OP level requires to finish digistruck peak on the previous OP level.