Hi Chris,
I'm sorry about the problem. MIDI and MPE can be a confusing mess.
I noticed that your video didn't show your assigned Per-Note channels. (In Per-Split settings, the View column [2] is set to show only the assigned Main channel and not the Per-Note channels.) This is important because you're using Channel Per Note mode, so each touch's messages are sent over those channels in rotation, not the Main channel. My guess is that your assigned Per-Note channels for the right split don't match the assigned receiving channels for your synth.
I also noticed that Timbre/Y is set to CC1 for both splits, not CC74 as you state in the video.
I'm wondering why you're using Split mode if you're sending both splits to the same synth? Split mode is intended to use with two different synths, one for each split, for example bass on the left split and piano on the right split.
You're using LinnStrument's Channel Per Note mode, so I suspect that you're intending to use MPE. If so, then I notice that you're using non-MPE assignments. It's hard to tell from your video but I think your synth is Animoog on iPad. If so and if your intent is to use MPE, then I suggest that it would be much easier if you simply set both LinnStrument and Animoog for MPE:
1) In LinnStrument, in Per-Split Setting, hold ChPerNote for 1 second. This will change all other relevant settings for MPE use, Lower Zone. (If you're running an old software version, this may not work, so please update your LinnStrument to the current 2.3.3 software.)
2) In AniMoog, set its MIDI settings for MPE, Lower Zone.
If you want to use Split mode, then you must use a DAW or MIDI routing software in your iPad to create a second instance of AniMoog, which will permit a different sound for the second split. Then:
1) In LinnStrument, in Per-Split Setting, select the Right Split, then hold ChPerNote for 1 second. This will change all other relevant settings for MPE use, Upper Zone.
2) In AniMoog, set its MIDI settings for MPE, Upper Zone.
To make it easier, please send me an email at the support address. If you like, we can do a video call in which I can step you through the process. There's also a helpful page on my site's LinnStrument Support page called "What is MPE?" that will help you understand MPE concepts like Main/Master channels, Per-Note/Member channels, and Lower/Upper zones.