Which is intriguing, as the Abyss and Nine Hells were explicitly part of that 3e FR planar system as well as well. Are they DMs Guild legal as well?
(By the way, the Blood Rift was just a re-skinned Gray Waste, and the Towers of Night just an expanded 2e Palace of Loss)
Yes, any plane mentioned in a Forgotten Realms is allowed, woth the caveat that not all elements are usable, like the domain of a Dragonlance God would out of bounds, but general stuff is fine. For example someone did a pdf on the plane of Archeron on dmsguild.
The Towers of Night was more then just an expanded Palace of Loss, they made it the largest 4e Domain, bigger then Hell even. It had space for Talona, Sseth, and Zahir, and all kinds of enviroments like swamps and jungles.