Can you start the Apreggio with the new performance automatically at Montage7 without pressing a button? Who knows what?
I'm still a novice on this thing ...

No. Arpeggios are always started by triggering a Key on the Keyboard where the Arpeggio is assigned and active (On).

In order to start the Arpeggiator the following three conditions must exist:
1) the Arp Master [ARP ON/OFF] = ON
2) the Arp Part switch = On
3) you must trigger a Key on the Keyboard within the Note Limit and Velocity Limit settings for the Part Arpeggio.

From the HOME screen
Select the PART
Press [EDIT]
Touch “Arpeggio” > “Common”

Here you can see the “Arp Part” and “Arp Master” boxes, both must be active (green).
You can also see at the bottom, the “Note Limits” and “Velocity Limits” that define controlling the Arp assigned to this Part.