Czech version is a bit anti-climatic, especially if you're a native Polish
I think "No, I am your father!" should be an acceptable answer to this text :)
Luku, probably. It is unusual non czech word and those are sometimes complicated to make vokativs for even for a native speaker.
There is Czech version of Luke, however. Seeing how the lands of Bohemia have been historically Catholic, it is to be expected that so important a Saint as one of the gospel writers would have a Czech version of his name. Lukáš. Vocative case would be Lukáši. https://cs.wiktionary.org/wiki/Luk%C3%A1%C5%A1
There is likely a Czech version of most 'traditional names", Kryštof comes in mind for Chris :)
But translating them outside of historical figures is unusual and a road to linguistic hell. We could as well translate Skywalker and end up with Lukáš Nebechodič.
I presume that declining proper names is important for Czech names only in a context of Czech culture and its language. Strange names, telling about books, films and foreign cultural or touristic facts should not be considered for declination, in many cases.