you probably dont need to "attract" bees, most common vegetables these days are self fertilising, and if they need fertilising ie fruit trees or pumpkin the bees will come of their own accord.
To choke out weeds cut the grass as short as possible, place layers of newspaper or cardboard directly on the grass. shovel your topsoil or growing medium dirctly onto the newspaper.
Look at my photos above, see the veggie garden beds? they are made in exactly this manner. I grew the logs we used to make the surrounds from seedlings (10 years mind you) but you could raise the beds using many different "found" objects or building material. Planks, bricks, rocks, cardboard boxes (will last 6 months only but cheap to replace) hold the sides in place with stakes.
You don't need a watering system. I only rarely use the one I installed at great expense. Choosing plants wisely is more important.
