I was wanting to confirm that these can be anchored in the space of other classes and regardless if you are favored or disliked by that class, e.g., Caldari v. Gallente space, without danger or penalties, loss of access ect?
And are these complexes subject to attacks/invasion in .5 or higher space by others?
If somebody declares war on your corp or alliance, your deployed assets are not protected by CONCORD, so they can indeed be attacked in HS.
There is no restriction as far as deploying certain types of POS in certain spaces, but there is not really any point in deploying POS anymore when everything is shifting towards citadels, engineering complexes and, soon, refineries (none of which have factions, all of which can be deployed anywhere).
You can anchor a POS on any empty moon in highsec with no regard to standings or security. You may be shot by the faction navy or police, but not your structure.
POSes are on the way out though and I suggest you don’t bother with one in highsec. A Citadel or EC can also be anchored anywhere in highsec (or lowsec) and will not be attacked by NPCs.
That said, you will not be able to anchor either an Upwell structure or a POS in highsec if the local NPCs are shooting you as they will likely destroy you before you can complete the process. But if someone else anchors it for you and transfers it too you, you are fine.
And yes, your structures can be attacked in highsec (0.5 or greater) by other players. This requires a declaration of war however and gives you at least 24h notice before they can shoot your structure.