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Correct details can only be put on a death certificate if the informant knows them. In some cases a person has to be registered as "Unknown".

Do you know what happened to her husband?

There are baptisms for a daughter born 1941 and a son born 1943 on familysearch. The son's birth is indexed with mother's maiden name Brookes. So they were in Birmingham at least until 1943.

This is Annaliese's burial in Queensland:
https://www.findagrave.com/memorial/254178071/annaliese-brown

Her death can be found here (lists father as Johan Otten):
https://www.familyhistory.bdm.qld.gov.au/

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