RootsChat.Com

https://search.findmypast.co.uk/search-world-records/british-armed-forces-and-overseas-deaths-and-burials

You can search here with place = a ship.
There are various deaths with location as "Levenpool", none that fit.
There are three deaths for Male Unknown in 1956-1960, none that fit.

Other sources who might help (or at least be able to tell you how this death would have been handled)
RMG:
https://www.rmg.co.uk/collections/research-guides/research-guide-c1-merchant-navy-tracing-people-crew-lists-agreements
or the maritime history archive in Canada who hold a lot of records for British registered ships:
https://mha.mun.ca/mha/

It is very possible that the two sets of "Lukeis" families are not related at all, just a spelling concidence.

For example, the surname Martin is common in multiple countries across Europe, including England and France.  I wouldn't try to call it an English surname or a French surname because it has such a long history in both countries that the origins of any particular line of Martins are probably lost to time.

A more extreme example: the surname Lee is either English, or as another spelling of Li, Chinese.

The National Library of Scotland has a lot of older maps.
Here is one for the area from 1922 but you can find others on the site.
https://maps.nls.uk/view/75652145

https://specialcollections.le.ac.uk/digital/collection/p16445coll4/id/288428/rec/9
 In 1900, senior medical officer was J Bradley Hughes - your JH?

List of surgeons in Liverpool in 1900:
https://specialcollections.le.ac.uk/digital/collection/p16445coll4/id/288263/rec/9
closest to BO I can find:
Felix Brannigan O'Flaherty
John Brown Oliver

Of course if you can find a directory from around 1906/7 you might see some new names pop up.

On the familysearch catalog for this location, there seem to be some parish registers and also land tenancy records.

Some of these are only viewable at a FHC.