1- when can I give oats to my baby

He is 7 months old ..

2- which dals to be included in home made cerelac ..

3- in Vegis section which Vegis to introduce.; He has potatoes n lauki soup

4- when to introduce citrus fruits like orange n lemon

N when to give watermelon

5- can I give limbu pani to my baby ..
If any other suggestions please would like to know