Job leveling items confusion

[Niwashi]

Also it doesnt have furher quest options to continue to 65 and onward.

The continuation of the job quests (beyond the original 50 levels) also has a MSQ requirement. You need to have completed the ARR MSQ all the way through the 2.55 patch quests to do the 50-60 ones, and I'm not certain about the 60-70 ones, but it's likely to require finishing HW. That's most likely what's blocking you.

That gear was added to the quests later. You can get it from Revenant's Toll by exchanging the Antiquated drops from Snowcloak, and uh...a few other dungeons.

That's a different set. The Wizard's set is the original AF, the iLevel 50/55 set that has always come from the level 45 and 50 job quests. The iLevel 90 set that was added to the quests later is the Sorcerer's set.

Since the job leveling potion marks the quests as completed, it should make the Wizard's set available from the Calamity Salvager.

The Sorcerer's set is the one that comes (indirectly) from Snowcloak, Sastasha (Hard), or The Sunken Temple of Qarn (Hard). Those drop Antique Mail, Antique Breeches, Antique Helm, Antique Gauntlets, Antique Sollerets, and Antique Tassets, which aren't actual gear, but are tradeable for the corresponding piece of any job's i90 set.