A rabbit can be weaned by 6 weeks, but it is often suggested to allow the babies to stay with momma until 8 weeks of age even if they are weaned. It sometimes depends on the momma and babies though (from what I understand) and they may be 'ready' to be separated before 8 weeks.
Alfalfa hay is a legume and is fine to feed growing babies. It is too rich to be the only hay source for adult rabbits.
I'm no expert on nutrition but I've not heard of such a diet. I don't know if there is some reason such a diet is fed to this larger breed. I do know that there is question in the rabbit world as to the benefits (or detriments) to some of the items listed.
As for the wheat -- is that wheat hay? The following is a little lengthy, but I think it has good info about the various types of grass hays:
Grass hays include the following varieties: timothy, orchard, meadow, Bermuda, brome, wheat, rye, oat and barley. These hays are very high in fiber, low in calories, low in calcium, low in protein and most are low in starches. Though most rabbit societies and rabbit experts find no problems with feeding rabbits the ‘cereal’ hays (last four mentioned), I recommend these the least of the grass hays as the wheat, rye, oats and barley are hays grown primarily for their seeds, which are very starchy food items and NOT good for the normal movement of a rabbit’s small intestinal tract. If you insist on feeding these types of grass hays, I strongly recommend you at least shake out as much of the grain as possible into the trash and feed whatever is left over. Rabbits fed ‘shaken’ cereal hay may end up on the thin side due to some of these hays having relatively low nutrient contents without their seeds. In my opinion it is best to simply avoid these hays, and feed the other forms of grass hay listed above. Wheat grass harvested before it sets seed is an exception and probably is an excellent grass hay.
I'm seeing mixed info on millet seed. Generally, seeds are not supposed to be fed to rabbits (except black-oiled sunflower seeds). But I've seen places that say occasional millet is fine for a treat. The House Rabbit Society says this in one of their articles:
Unlike rabbits, however, you can give your chinchilla a small amount of raw or roasted UNSALTED nuts daily such as pumpkin seeds, sunflower or safflower seeds, flax seeds, millet, almonds, pecans and walnuts.
And this is what I found on milo also from the House Rabbit Society:
...carbohydrate and fat-rich seeds and grains such as oats, milo, corn, peas, sunflower seeds, potatoes, peanuts, puffed corn, cornflakes, popcorn, and dried fruits.
Seeds are high in fat and are important for wintering animals. Your house rabbit has no such need; in fact, the National Research Council recommends that domestic rabbits receive no more than 1.5% of their calories as fat.
Veterinarians have reported that rabbits fed seed-rich diets have a much higher incidence of fatty liver disease (hepatic steatosis), which is often fatal. These seeds and grains are also rich in starches. While some of this starch is digested in the small intestine, much of it is not accessible until it reaches the cecum. There it becomes a potent energy form for the cecal bacteria; unlike cellulose fiber, which slows fermentation, starch in the cecum is fermented rapidly and can lead to bacterial overgrowth, bloat, and gi stasis.
The "normal" bunny diet recommended for indoor house rabbits is....
for young rabbits (under 6-7 months, though this may be a bit longer for larger breeds):
unlimited hay (can be alfalfa or grass hay or a mix of both)
plain pellets for juvenile rabbits - free fed provided that bunny eats generous amounts of hay (otherwise the pellets may need to be somewhat limited to encourage hay eating)
greens can be fed starting at 12 weeks by introducing slowly one type at a time
for adult rabbits:
unlimited grass hay
plain pellets for adult rabbits -limited amounts based on body weight
2-4 cups of daily greens
