My memory is a little hazy on this on this because it was over a couple of decades ago, but didn't the original releases of Baldur's Gate 2 & Nevewinter Nights (2002) have relatively thick, spiral-bound manuals that included an extensive Players Handbook section?
Couldn't one's character give their extra (unneeded) magic items to henchmen or trade them with other PCs? I know I & others with whom I gamed did.
I would choose the Cloak of Displacement for my character, in fact in the past I had.
While you're correct in quoting from the 1e DMG that an AC better than 2 is possible, there is not an explicit statement that an AC better than -10 possible. In any event a DM could logically interpret that the section as meaning that an AC better than -10 is possible because it is not...
While it has been a very long time since I've read the 1e DMG in depth, but I recall reading somewhere that -10 is the best possible Armor Class outside of a unique, extremely high level magical creature such as a dragon or extra-planar denizen.
In the past there were some articles of D&D compatible material derived from video games in the print version of Dragon magazine that can be found via the DragonDex. I'll include a list of some below at the end of this post.
In the very late waning days of AD&D 2e & the early days of D&D 3e...