Can You load LP presets into the SP and vice-versa?
Sure, I do it all the time.
Works great! 
As long as both synths are at the same firmware level, there shouldn’t be a problem.
Randy
LP= Little Phatty
SP= Slim Phatty OR Sub Phatty.
Just to clarify, which are we talking about?
SP = Slim Phatty.
For all practical purposes, the SP (Slim Phatty) is a just rack-mountable version of the LP (Little Phatty), and can use the same firmware & presets.
SP is the abbreviation Moog started using for the Slim Phatty in the Owners Manual, long before the Sub Phatty made its debut.
Probably why a lot of folks refer to the Sub Phatty as just “Sub”.
The exception being that the Tribute requires different code; the feature set lines up [generally] but the hardware differs slightly.
I also do it all the time with my poly-chain (Little Phatty St. II → Slim Phatty → Slim Phatty). I do most of the preset writing on the LP (the primary unit, at the start of the chain), and you can send preset(s) (current or all slots) via the LP’s “SYSEX” Menu page, to the following Slims via the very same MIDI cable(s) which chain them!
I’m glad a computer or other interface isn’t required, as it makes the chain set-up much more self-contained and faster to work with when writing/saving patches. 
David.
NZ
I have a Tribute Edition.
The question is, if I create a preset bank on LP TE OS 3.1 and send it as “All Presets” Sysex, will the Stage I and II and Slim Phatty load them?
Anyone?
If you don’t get an answer here, perhaps send Moog Music an email directly..
David.
NZ