I'm not really an expert on these.  I don't usually see them at the end, but I can't say why not.

They usually represent the thing they stand for in a nominal way (rather than adjectival), so that gramatically, one could replace the other.  I don't think this works in your example.

I think I've read that the appositive must be a noun or a noun phrase.  I think that's what my dictionary says, in fact.

I like your dogs, big brutes.  "Brutes" is a noun; "dogs" is a noun.

mohzayat

“I like your dogs,they are so cute. ”

This amounts to a "comma splice."  It needs either a conjunction or a semicolon.

I like your dogs because they are so cute.

I like your dogs; they are so cute. 

Best wishes,  - A.

Edit.  I wrote you a PM explaining why your salutation "hi dear" might be inappropriate, but after I had finished it, it got zapped, because you have opted not to receive PM's.

Your profile says you want to chat and exchange views.  Maybe you should check it out.

We name phrases sometimes for the type of word that "fronts" them (heads them), and sometimes for the way the phrase functions as a whole.

So if an infinitive phrase functions as subject of the clause/sentence, you can call it a noun phrase. 

To kill a dragon has always been my idea of a real adventure.

My dream, to kill a dragon, has finally been realized.

And of course "gerunds" always  function as nouns.    - A.