I'm having a hard time finding an accurate video or website, but this has some general info.
https://www.animalsaroundtheglobe.com/possum-vs-opossum/
A couple of quick corrections are:
1. The North American Virginia Opossum is always called a "possum."
The only person who ever wanted to argue this was a 12 year old. I'm glad he read something about that though. Technically our possum is called an Opossum, but I go with Granny Clamper on this one.
2. The article says they are mostly scavengers. That is incorrect. That's only a small.part of the diet. They are opportunistic and eat very many things. Mice and tick populations are decreased by their feeding behavior.
I believe that your possums are herbivores, but our opossums are omnivores.
My guess is that they had the same parents going back to the ark and like many creatures, they developed unique traits from genetic diversity and isolation.
Nobody knows for sure. The main similarity is that they are all marsupials.
I disproved a commonly held belief about our own possums when I raised orphans. They were very intelligent. The juveniles were quicker to learn than dogs.
Anyhow, you got me started so I have to resist the urge to write an article.
I used to teach, so I tend to go into more details than sometimes I should. Lol
Your country has an amazing variety of possums. I think you are blessed to have one visit. Do you feed a dog outside or what do you think attracted him to your porch? That would be startling to hear thumping. I heard that a couple months ago and it was someone trying to break in.