1) Everyday when I read the Quran, I always gift it to Imam Al Mahdi (may Allah hasten his appearance). I do this all the time I read a surah so is it okay to gift it to him everytime(everyday when I read)?

2) If I had a niyah of doing khatma of the quran, could I still gift what I read to the Imam? For example reading a couple pages a day continuing while in my mind I have a niyah of finshing and doing khatma of the Quran, could I still gift whatever I read at that time. And in addition, once I complete the whole Quran inshallah gift it all to the Imam al Mahdi?

1) Not only is it ok but it’s highly recommended. Please continue doing that. And yes you can gift that to any of the Imams or Prophets.

2) So first you make your niyyah of the Khatma (you gift it to so and so marhoom, for example). Then you will say: Oh Allah, I gift the reward of offering my khatma to this marhoom for Imam Mahdi (a). You can do that