@xander, What are you using to enter text into the forum... the capital letter on the front of every word makes your post very, very difficult to read. Exhausting. If you are doing it on purpose, please stop. If your translating device is doing this, contact the maker and tell them you received feedback that it does not work correctly. Thank you.
User Arpeggios are saved in the "Arpeggio" folder for the current User Bank.
Touch "Data Utility".
When you setup User Arpeggios within a Performance, they are stored as linked parameters with the individual Part. The Part is stored within the Performance. This way you can recall the Part whenever you require it (in any other Performance) and you can elected to bring those linked arpeggio along or not. It is your choice. And yes, it is very helpful.
Arpeggios are not a part of the program in which they are used, they are simply linked/associated with it. They are musical phrases that can be freely linked with any Part within any Performance.
I will have to look into the details of managing Arpeggios. There can be a maximum of 256 Arpeggios in any Bank. My understanding of the specification is that when you Import data from a Library, the data is earmarked with information that should collect all of the data needed to make that data work in its new location... so that when you then create a new Library file, it should then include all the data you require to make you selected data work in the new setting. If you are reporting that this is not happening, I cannot confirm this right now - with NAMM (the big trade show) going all this week, while I'll be very close to Montages all week, I will not have time to take a close look at this until middle of next week. Sorry. But the act of IMPORTING I understand, is the key.
Arpeggios are phrases and need to be managed separately, a phrase is something a guitar plays, it is not a part of the instrument. It is something the musician performs on the instrument. But the phrase is not permanently associated with the instrument. You need to be able to manage them - you temporarily link individual phrases by activating an Arpeggiator for a Part, you can then link eight phrases, Arp 1-8, with that Part... using the Arp Select grid.
Managing Arps between Libraries is a subject of importance, and we'll add it to a list of items we need more clarification/documentation on. Because like User Curves, Songs, Motion Sequences, etc., the act of combining these from various Libraries will be of interest to many folks as time goes forward. Have you tried the IMPORT LIBRARY function when combining your Libraries. Does this not affect Arpeggio Phrases? (You may have said this in your post -but it was just too physically exhausting to read - although I think I got the gist of what you're talking about).
Let us know.
Your question about editing a MS LANE... it is two completely different things to edit an existing MS Lane and creating your own User Motion Sequence. I may not have understood what you're asking... but when you enter the "EDIT SEQUENCE" box, you are creating a custom user Motion Sequence. Study by exploring the LOAD SEQUENCE and EDIT SEQUENCE options on the "Lane" screen.