Ayon, whether to get 7 in 1, 9 in 1 or 10 in one for that matter, leave that on the vet to decide. They are professionally competent to decide what suites best for our dogs.
You can feed commercial dog food to your dog. There's no problem. However, as he grows older, lets say when he's six months old, start phasing out kibbles and introduce home-cooked food in his diet. This will be good for both of you. Home-cooked food will be cheaper and you'll be able to save money in the country hit by inflation. You dog will also be happy as he'll be able to comeout of the monotony of same dog food offered by his master.
Ayon, if you could try to increase your budget a little, I'd suggest you to feed him Canobites. It'll not make your dog over-weight and will control his stools. I've personally tried the product and found it beneficial.
Replace milk with curd and instead of feeding chappatis, introduce rice . I'll not make comments on supplements as they must have been prescribed by the vet after analysing the puppy's state.
Replace marie-gold biscuites with dog buscuites. You must also feed chew-sticks. These products are meant for our dogs and they give good jaw exercise and keep them busy.