(I used mieć as a generic example, but I don't think there's anything special about it here, right?) -
yes mieć is completely generic in terms of conjugations
you got all examples correct
the only thing
Koń, miałeś kwiat.
should be 'Koniu, miałeś kwiat' (and similarily Rybo, miałaś kwiat). - in sentences like that you sometimes need to use vocative (it is a direct adress) - I think historically you always needed vocative in such cases - now most male first names tend to be used in nominative in such personal adresses, female first names can be used both in vocative or nominative but vocative is perceived as affectionate contrary to vocative in such, then you very often need to use vocative if you are addressing non-persons (animals and objects) cause nominative looks strange (of course you don't see people addressing objects that often ;P)