I believe your child has been suffering from throat infection
and subsequently got tested for strep infection.
The cough can be stained with streaks of blood in severe and chronic cough
but it important to treat such infections with a course of antibiotics.
Your child must be having altered taste
sensation and it is probable that what she says of tasting blood may actually be either mucous or altered taste.
A problem running for one year now needs evaluation with an ENT specialist
Acid reflux causes vomiting and heart burn but these are not precisely his complaints.
A long standing problem like this can result in weight loss
So get your child evaluated soon.