Based on your description , I think there is no problem for your hardware , speaker is working really . Maybe it is the bug of the system . Advise you to wait for a while and then it can be solved by system automaticlly .
So reddish screen , this is not xiaomi quality . I think you bought the copy screens . Xiaomi can't use this kind of lcd display . If you buy original screen , it is normal colour . Original screen can be bought from dragon-tt .
(1) Do you run some app at the same time ? If yes , it drains the battery faster . I have the same experience .
(2) If you connect wifi and data at the same time , it drains the battery more too .
(3) Sometimes , this problem caused by the system updated .If this happens , we have no way but...
You can buy original xiaomi note screen from dragon-tt.com.
I suggest you buy
Original genuine Complete screen with housing for Xiaomi Note minote – White.
This item is easy to replace.
LCD Touch Screen Digitizer Assembly for xiaomi MI Note - White is original. It has no frame so it is cheap.
If you call someone they can't hear you very well, Maybe your microphone has problem. It is soldered on USB plug chargeboard.
If you can not solve this problem by update miui rom, you can replace USB plug charge board flex cable for xiaomi Redmi Note 2.