1. I think dummies should be account-bound rather than character-bound, since furnishings are generally designed to be put in the bank and accessed by any character in your house. However, if it was a discrete furnishing item rather than a collectable, and it was still in a character's inventory when the character was deleted, it's gone. If you had furnishings in your bank, or in a house, I presume they would still be there even if you had deleted all of your characters. (You might check around in your houses if you haven't already.)

2. On the party list, there are buttons to toggle between normal and vet mode. Just set it how you want it before the first party member ports in and you're good.

Dummies are basically a piece of furniture. If it was in one of your character's inventory and you deleted them, it's gone. If it is randomly in a house or storage chest, it should still be there.