Yes, check the 'other' possibilities before taking the engine apart, maybe (remove the plugs and) put it into gear and push the bike and see what happens.
About the 'hydraulic locking' (IMO not very realistic that would happen but would be quite interesting if it was the case), if the combustion chambers were full of something, remove the plugs and have a look, for the crank try draining the sump and see if some vast amount of oil comes out.
And welcome to the forum, as always, intro post in Bikes & Members appreciated.