Murdoch is not as dominating as his father. He will surely recognise your position as heir to the throne and appeal to King Henry V of England for your release.
You do not trust the Albany family as far as you could catapult them. However, Murdoch has inherited the authority of governor. Get in touch with him and promise that he will receive your favour if you are released.
Not a good idea. Firstly, returning to Scotland as a vassal king under Henry V would be unpopular among the Scottish political community and disregards eveything your predecessors have fought for. Secondly, you are too ambitious to submit to overlordship. You have been imprisoned for 18 years, you want to be free once and for all.
Which card will you play?