Artifacts will disapear from the artifact screen, so there's that.
Oh, and yes, stuff gets out of cages. So either slaughter your POWs, or dispose of them in some other way.
I suggest you carefully plan and build your necro-containing room now. Add an entrance with a rising bridge which can be operated from the inside. Add statues for a statue garden, a barracks, workshops, everything that a dwarf could need. Try to make the barracks overlook the raising chamber.
Now, when you create your adventurer, try to see if you can make him/her be from your fortress (remember your civ's name). While you're making your adventurer, give him/her very low empathy (seeing zombies or your own dwarves dying can be hard on their stress). Make him/her invulnerable to stress, a total loner, make him/her hate family and friends. That way he/she won't need contact with those. If you can, make him/her dream to master a skill or become a legendary warrior
The best way to get a slab/book is to become a vampire. Just topple a statue at a temple. Make back up temples for many different gods, just in case they don't feel like cursing you on a general temple. Undead won't attack you then. Just walk in and grab every book.
Now, if you haven't figgured it out already, you will be using your adventurer as the necro. Once you come back from the tower, leave the books at the library, grab a pick in case you need to do some remodeling from the inside, walk into the necro-palace, and close the bridge.
If you never manage to get your dwarfs to become necros, oh well, you'll already have one. Make sure to order your adventurer to destroy the lever once you unretire. You may have problems with his/her thirst. He/She won't die because of it, but with no bozee he/she'll become slow. Even of he/she wasn't a vampire, a necro doesn't feel thirst either, but still need alcohol. Maybe use a non-dwarf species. Goblin, maybe? To justify being trapped all eternity?
Meh, just have fun with it.