I have not directly used an FE pump in a MEL, but understand that they are interchangeable (after vacuum pump was deleted-later models). The intermediate shafts do have different PN's and and the Shop Manual gives a MEL shaft length of 2.24-2.26". The FE has one retaining ring (metal to bottom) while the MEL has two. The metal one is at the top on the shaft, the second (hard rubber is at the bottom and must control penetration length.
Here is the assembly (oil and vacuum) mounted);
Here is the check valve on the left side of the block skirt;
I think (not certain) that someone previously could not find a MEL shaft and tried to get by with the FE.
As for distributor shaft depth, this is another blind area at this point. Do you see a casting I.D. No. on the distributor bowl? Some distributors may interchange, some may not. MEL had valvetrain problems in the first year and they changed cam journal sizes, valve sizes and heads. I have no tech info for the 410 EDSEL, so have to play it by ear here.
