Just on Tybalt -- hard to know the case for individuals especially when you can't see them
, but this sounds like a large amount of food even for an adult -- is he getting half a large tin, or a small tin? Even at a small tin, he is eating at my conservative estimate, just over 1.5 cups of food daily plus treats on top of that, or if half a large can, over two cups of food. It does sound like he is a pretty big puppy anyway if he is 13lbs and was born in March (not sure if that is right but guessing from your sig?). But most puppies and indeed adult dogs would not eat more than about a cup of food a day. Most puppies will only eat what they should eat but some are gluttons and must be tightly controlled. If he is really oversized -- then this amount may be right for his size and growth -- but you might want to check those amounts with your vet.
On my group:
Jaspar: 16.5-17 lbs, eats 3/4ths cup of food daily
Leo, 15.5lbs, eats 2/3rds to 3/4ths cup daily
Lily, 12.5 lbs, eats 1/3rd- 1/2 cup of food
Lucy, 13 lbs, east 1/3- 1/2 cup food
What they eat: varies all the time. Homecooked stews, leftover soups, sardines and kibble, kibble and salmon oil with various extras, sometimes raw necks or wings (in pieces), sometimes cooked beef or chicken mixed with kibble. Kibble: generally rotate between James Wellbeloeved and Royal Canin. Currently eating their way through a bag of JWB fish flavour.
All get a fair amount of exercise -- 3-4 walks daily.
Various treats: fruit, veg, dried meat treats, dried fish treats, greenies, etc.