MAE was Apple's fascinating attempt to run Mac OS on Unix workstations, essentially creating a compatibility layer that translated Mac Toolbox calls to X11, allowing Unix users to run Mac software without actual Apple hardware.
There was a 3rd party toolkit called I believe Equal, then Lattitude for porting Mac Apps to Unix. Equal was used to port MS Word & Excel, and Lattitude for porting Adobe Photoshop and Illustrator.
It was essentially a reverse-engineered MacOS Rom Toolkit. It implemented most of System 7 as well as QuickDraw.
(author) MAE isn't the basis for Blue Box, though I'm quite sure it informed its design. Blue Box/Classic is actually more like MAS, the aborted Mac compatibility layer for PowerOpen/AIX/"A/UX 4," in that it runs PowerPC code directly on the CPU in the "problem state" and uses a paravirtualized operating system and enabler. There is no processor emulation in Classic except for supervisor and faulting instructions.
There are also differences at the level they execute: MAE can, and was designed to run, as an independent process like any other well-behaved X11 application, and multiple users can run multiple sessions of it, but Classic/Blue Box needs operating system support and only one instance of it can be running on a system by a single user.