Migration from Rpi1 -> Rpi2

[Nachteule]

So, did this procedure, was successful

That's what I did:

1) replaced my devel RPI2/3 root subvolume against older (from May) RPi1 root volume (Jessie os) and activated this volume.
modules and home subvol was unchanged, so there was no need to replace kernel
2) changed Raspbian -> Debian in /etc/apt/sources.list and rpi-jessie -> rpi2-jessie in /etc/apt/sources.list.d/xbian.list
3) modified my /etc/hostname and /etc/network/interfaces to avoid network conflicts
4) run apt-get update;apt-get upgrade
5) apt-get breaks after a while because of missing link
sudo ln -s ../init.d/mountkernfs.sh /etc/rcS.d/S04mountkernfs, added this link
6) run apt-get upgrade again
7) while upgrading network connection was broken, no idea why (was using ssh connection), but in the background apt-get continued working
8) was waiting some time (dinner and cleaning kitchen)
9) restarted RPi3 (hard reboot by power off/on)
10) system comes up, and ALL packages were installed. So, I can not reproduce your second issue, sorry
11) had one issue now: when Kodi stops, got no command prompt, only strange error message from splash, so
12) I reinstalled xbian-package-splash and linux-image-bcm2836 package (to make sure that initramfs is rebuild completely)
13) rebooted and everything is ok now.