Welcome to ribnet
Loch Lomond you'll definetly need to register - its £5, and once paid, you're registered for life - they'll send you a " do you still own this boat / anything changed" form annually, whch you send back & they send out your reg. plates for the year.
for a start.
Caley canal I think is similar to the other Scottish canals - you can get various "tickets" depending on what you want to do, but donlt need a full blown registration. http://www.scottishcanals.co.uk/
is a good place to start.
No idea about your other planned venues, but I'm suire someone local to there will be along soon to advise.
And I'm sure as it's a cruising area type Q, it'll probably stay here!