I know this is an odd question, but here goes.

The hole cutout where it retains the lifter, kind of a rectangular hole where you attach to the lifter,
is this somewhat standardized ? In other words, can I maybe use a Crane Mopar linkbar on a Comp Mopar lifter ?

Only if they fit properly, I have several different brand link bars that are not interchangeable with some of the other brands

Here is the Comp Cams info.
I measured my BB link bar's slot as 0.325" tall x 0.69" wide (curved ends of slot).

If you can get other brands info, they could be compared to see if they might work. FWIW, I think the Comp link bars are longer than needed (2.68")

Jim, Wow ! That's amazing, Thanks very much !

Since Comp uses the same link bar for the Oldsmobile engine with the wider lifter bore spacing, I est that a link bar with both the "A" and "B" dimensions could be almost 0.077" smaller and work on the BB Mopar Comp lifters. The slot would need to be close to the same size, just closer together "A"