How to say : "It looks like we have to wait for Minji before eating it all" ?
My guess : 다 먹기 전에 민지 씨를 기다려야 되는 것 같아요
^ is it possible to say it like that? I have to create the sentence using "(으)ㄴ 것 같다" construction.And casual form :

다 먹기 전에 민지를 기다려야 되는 거 같애

Question

How to say : "It looks like we have to wait for Minji before eating it all"  ?
My guess :  다 먹기 전에 민지 씨를 기다려야 되는 것 같아요 
^ is it possible to say it like that? I have to create the sentence using "(으)ㄴ 것 같다" construction.And casual form :

다 먹기 전에 민지를 기다려야 되는 거 같애

Answer

You are almost correct, but I think it needs to be more natural.

다 먹기 전에 민지를 기다려야 "될" 거 같아. 되는 -> 될

But, you can say like that and we can know enough what you mean. :D

Answer

Yes you're right. For the casual form it ends with 것 같아

Ne manquez pas cette occasion d'apprendre une langue depuis chez vous. Découvrez notre sélection de professeurs de langues expérimentés et inscrivez-vous dès maintenant à votre premier cours !