Halal-liha hiipii kauppoihin hiljalleen

Elämääni ei juuri liikauta se hiipiikö liha vai ei.

'Meidän' is the genitive case of 'me', the equivalent of 'our' and 'us'. 'Meille' is a bit similar but I don't think there's a direct equivalent to that in English language, but usually it's used in place of 'to us'. 'Meille' can be used when 'me' or 'we' is the object of a certain action, for example "That apple belongs to us" would be "Tuo omena kuuluu meille", "It doesn't concern us" would be "Se ei kuulu meille", "That might be of use to us" would be "Siitä voi olla meille hyötyä" and "He moved in with us" would be "Hän muutti asumaan meille." The suffix '-lle' would indicate that 'meille' is the allative case of 'me' or 'us', but from skimming through the Wikipedia article I'd say that its usage in Finnish language is a bit broader than that so I'm not entirely sure. Note that I'm not that well versed in linguistics so you shouldn't take all of what I said for granted, I'm merely trying to point you in the right direction.

Kun ei kelpaa halal-liha, niin pitää saada sakkolihaa!!!!!!!!!!!!!!!!!1

Leviää tai levittäytyy lienee parempi. Hiipii ei ole oikeata kieltä.