The amount of pellets is ok, and you you are right rabbits do not need a lot of pellets.. Now as far as the hay, he should be eating a lot of a hay and about 2 cups of fresh greens ( veggies ) daily..
As far as plants some are dangerous to rabbits so watch out...
Veggies that are safe are..
These foods should make up about 75% of the fresh portion of your rabbit's diet (about 1 packed cup per 2 lbs of body weight per day).
Leafy Greens I (need to be rotated due to oxalic acid content and only 1 out of three varieties of greens a day should be from this list)
Leafy Greens II (low in oxalic acid)
Kale (all types)
Red or green lettuce
Mint (any variety)
Basil (any variety)
These should be no more then about 15 % of the diet (About 1 tablespoon per 2 lbs of body weight per day).
Broccoli (leaves and stems)
Edible flowers (roses, nasturtiums, pansies, hibiscus)
Bell peppers (any color)
Chinese pea pods (the flat kind without large peas)
Cabbage (any type)
Just a note to add, as far as pellets Do Not buy pellts that have ant dried fruit, corn, nuts, seeds or any crunchy things in it, this is a low quality pellet most rabbits will pick out the naughty food and not eat the pellets... So stay away from pellets that have this in it... Naughty foods can contribute to fatty liver disease, cecal dysbiosis, obesity, and otherwise cause health problems.
Some types of seeds (especially things like "Canadian peas" and corn kernels) have hulls that are indigestible to a rabbit, and can cause life-threatening intestinal impactions/blockages.
Owner of a house rabbit...