Guild Wars 2

Do I still get a shot at ascended gear and loot after the first time doing it that day?

you get to loot the chest one time each 24 hours on each worldboss. This is accountwide, so do not work to switch character.

Doing it on alts works for me, teq too gives me the big chest with 1g and 3 smaller chests when using alts

You will only get Great Jungle Wurm Chest (Statue chest) once per day. But The Wurm’s Bronze/Silver/Golden Chest you will get every time. And i believe that it is only the statue chest which have possibility to give ascended.