I've been wondering whether Min is only used with en words and Mitt with ett words?
That's entirely correct. All plurals are mina however. Have a lingot as a reward!
So plural (My cats like milk) would be
"Mina katter tycker om mjölk."?
That’s entirely correct!
Tack så mycket!
I have been wondering about that and now I know
What does "om" mean?
Well as far as I am aware it is just part of 'tycker om' which together mean 'like' or 'likes'
If I read this sentence in dutch means, ‘houdt van’ means in English ‘loves’. But the exact translation means ‘Love about’ or also; ‘Loves of...’ . This maybe the same for ‘Tycker om’ if I’m right.