- Remembering his power of perception, yes; he can notice there's something particularly off, though he may not entirely be clear. He would be able to notice there's a type of energy surrounding the doorway, and further in; a keener sense will be able to inform him that it's similar to the same energy that's all around Jinnjar.

But be warned that the more he focuses on using this power out of the illusion, he will feel a draw back 'into' it - that is, his old life. He can snap himself out of it, he just needs to be careful.

- Roland can break out of it, yes! Books on Diagad have a similar energy to the one above, though again, his power of perception may work for or against him in the case of any books.

As for history, everyone has a very similar idea to Diagad's history. Usually they remember up to the point where Jinnjar grew to be known as the capital of Diagad itself, creating the equivalent of the Justice League in space, and its relationship with other planets. But someone with experience with history may realise that everything seems rather...perfect. Like a one-sided story that paints Diagad - and Jinnjar - well.

The history classes in any school will have the same energy as the government buildings too.

- Use of Arms Band/hammerspace in general: No! Since people have such a variety of powers, people would just assume it's a power or some trinket.