there is no way to alter the kernel used, OK .... but on the other hand I have not hit a problem, that I recall, when doing normal updates of the live session.
It is also possible/likely that I just did not meet with a problem waiting in the wings ....
Regarding larger packages, like LO, if those are added while running on a PC with sufficient memory for the purpose, then they will be available for later use on less well-endowed PCs.
If, for some reason, there is a large number of updates, sufficient to require a greater amount of RAM, then those updates could be applied in stages during the one live session ........ do, say, 10 packages, downloaded to memory, installed and cache cleared, do the next 10 .... and so on until all are updated.
can i make a live CD or live USB that accepts and saves changes in the updates and changing the installed apps??
Apps you "uninstall" won't actually uninstall ...... they will still be contained in the OS.
Apps you add, while using "Persistence" will be added to the 'Persistence' location and become available as additional apps when booting with Persistence. They are not available when booting in standard mode.
Persistence is not available on on a liveCD (cannot write to it) but is on a liveUSB.
Having said all that ... there appears to be a way to save personal files (and maybe OS updates?) to a USB or other location, when running from a liveCD.
I have never used it or tried it, as the idea of using two separate pieces of media was not very convenient, IMO.
No doubt, to get the best and most convenient set up, one might start with a 'mini' install, eliminating, adding and updating as required, and then make a remaster for use on a CD or USB device.
After that very little should be needed to be stored within the 'persistence' location of a liveUSB media.