Does the following have any mistakes? Yes. Better are: I've chosen a special gift for you. I've chosen some special gifts for you.

Hi Botir, I understand your question. As a native speaker I feel like the way you wrote this makes the gift seem like its very special, and kind of secret. If you say "I have some special gifts for you." I would be really excited to get the gifts. I think it would be helpful for you to remember that "some" is similar to "many". So if you say some it has to be many gifts. You should say "a special gift" (one gift) OR "some special gifts" (more than two gifts) Good luck with your gifts!

In spoken english, you wouldn’t say “does it has” or “does it have”. You would say “is this right” or “is this wrong”. Also, you’d say “I have a gift/present for you”, or “I bought something for you”

There is a mistake is in your question part. You are using the auxiliary verb 'to do' to form your question, therefore the other verb should be in the bare infinitive. Does it HAVE a mistake? It would also be better to say '... a special gift...'

No... its right