Yes. There will be "some" PvP allowed on Arboreus. Just how much area has never been officially stated. What has been stated, however, is that there will be no reason for a beastman to travel to an PvP zone on Arboreus unless that is what they are looking for, as there will be no special resources found in those areas.
Also, Demons will only be allowed in those PvP zones due to a very limited time schedule that they are ever allowed to be on the planet.
I have talked to @Prometheus about the %, and we are hoping that he will agree that Arboreus should at least be 80% if not 90% free of PvP. He has also stated that they will work hard on keeping the PvE content on Arboreus updated and fresh.
There will be PvE on Tartoros as well, but you are able to be killed the entire time you are trying to do PvE there
As for the loot, I have never heard a definitive answer on there being Full Loot on Arboreus. I am hoping that they make both the city structure and looting different on Arboreus than they have on the PvP inclined planets as the dynamics on that planet are just "different" all together..