Yeah,i understand your points,but i think there are ways to fix the mistakes i made.For example,what if a wandering herd who just arrived to the great valley starts to speak about a disaster,noticable from distance becose herds aren't going to the land of mists,like a big fire,or whatever,which makes the gang worried about Thickles.If i remeber correctly,Ducky seemed to especialy like the little rat,so i think she would remember him,and try to check if Thickles is fine or not.
I'm just saying,that there's a thing which can make them go back to the land of mists,becose they actualy left a friend there.It's minnor matter,how they get to know that he is in trouble.
For Thickles,i agree with you.He is definitely not the most memorable character in LBT.I even forget his name,and i was too lazy to look it up.Thats why i called him little rat like thing.