War on Kryta Oppressors weps

I only recently came back to the game after several years break.
I need several of these weps to help finish my HoM as they seem alot easier to obtain than extra tormented ones.
I did the whole quest chain on my main char and got 1 wep with a few medals left over and started doing the daily wanted quest. it seems to give a pathetic amount of supplies i think one of them gave me 4 on Hardmode.
I have 2 accounts full of max level pve chars /w gear. Is it possible to do the original quest chain on different chars and give the weps to my main or is it a once per account reward?

The WiK chain is once per char, not account. You'd definitely be able to finish the chain on any of your chars and give the Oppressor weapon to your main.

You can also do the follow up quests about the Gwen & Thackery storyline for more medals - I remember those giving you a decent amount of medals and gold. That quest line becomes repeatable and is a good way to farm war supplies (25 for 1 medal), gold and Vanguard points.

Yes this is possible.

Also, you can definitely stalk the wiki to cherry-pick the quests that give out the most amount of supplies so you can get medals. I think it usually takes me 3-4 weeks (if not less) to collect enough supplies to get 10 medals.

As long as your other characters meet the requirements for starting War in Kryta (finished either Prophecies or Eye of the North), they are eligible to do the quest chain, yes. You can do the quests on any character and put your rewards in storage for whichever character to redeem. The weapons are only customized upon display in the HoM.

If you multi-client your second account, you could speed things up by having characters on your second account leech to cut the time. Just be aware that War Supplies and Oppressor Weapons can be traded between accounts, but Medals of Honor cannot.

If you can handle it, Hard Mode gives higher reward and is worth considering. Especially for the initial bounties.
Also, a lot of the daily Wanted quests really aren't worth the effort. Most I will only pick up if I'm doing the WiK quest they're in. Otherwise I usually just save up the 3 Kessex Peak dudes and fit in Calamitous and Greves when I feel like it. A HM jaunt into Kessex with a leeching secondary can yield a good number of War Supplies.

Yes it is. I have 7 characters qualified to go fetch war supplies. This means the same quest 7 times which gets boring a bit, but the stacks of 250 grow fast. Medals of honor begin to stack up too. This is worth doing if you have multiple characters you can qualify. Finish Prophecies, have MoX and do EoTN up to point of hanging tapestry from Asuran quest chain in weapons slot. This seems to turn on qualification. Go listen to trial, go listen to Salma dialogues. start grabbing quests from board and like that.