Golly, they sound fierce little critters. LOL. You are so lucky to have them though. Our possums here are super cute too, but they only come out at night. I do have a photo somewhere of one perched up on a post. They're nothing like the possums they have in the States.
My first Ch cattle dog, Shady, was a typical cattle dog in that she'd be very much on guard when strangers were here, did bite one, put the wind up others, wanted to get out and give the cows Hell, wanted to fight the other girls etc., but one day a possum was trying to get across a piece of polypipe that protected a power line above her head and it fell off. Plop! Straight onto her (rather broad) back, and clung to her hair. Then it ever so slowly slid down her side and the darling girl just turned and watched it. LOL. I was so proud of her ..... but had she tackled it, well I've heard they can scratch you up pretty bad. Don't know if they'd bite as well though.