As Robin said start at the top & work down, on the
plus side what little oil you had would be going to
the crank so the bores would probably nip up first.
As for the leak, if it only started after after the
lock up then it's probably down to over pressure in
the crankcase due to knackerd rings/bores you'll
just have to dig till you find it.
I had a hose let go a few years back, motor locked
at 70 mph and got away with re bore pistons & rings
hope you get lucky too.

Legion.