The books are their own canon that is somewhat internally consistent. The various TV series adapt various things from various stories, but are usually individually internally consistent.

But with the comics, Tove just did whatever the hell she wanted. You will not find consistency over their full run, except within each “story”. She also goes a lot harder with societal commentary, and the characters are more “caricatury” compared to the more complex complete people she writes them as in her novels.

Cartoonist Jansson is a very different writer compared to novelist Jansson.

Note that this is Snorkmaiden and Moomin, not young Moominpappa and Mamma. Moomin and Snorkmaiden receving the house as a couple makes little sense in the wider canon, in which Moominpappa is known to have built the iconic blue home of the Moomins, personally. (He did so once he and Mamma decided to start a family. He lived in a different smaller house that he also built, before meeting her.)