Unless the pair of angels are a mated pair then things will get pretty ugly. Angelfish are cichlids and almost all cichlids have an attitude. This gets even worse when they are spawning. They will chase away anything that comes near. If you want a spawning pair of angels, you won't be able to keep the rummynose in the tank.
A better centerpiece fish would be a smaller gourami like the dwarf or the honey gourami. I have a 29 gal stocked with three honey gourami and twelve tetra. Everyone gets along just fine. Honey gourami are the most peaceful of the small gourami. Larger gourami like gold gourami will not work in a tank that size.
As for the bottom dweller, a rainbow shark is not a good idea (read more here
). They grow to 6 inches and need a larger tank than a 29 gal. Most places recommend a 55 gal or larger. It's not that they need the large water volume, it's that they need a large surface area as they are active. A better single bottom dweller would be one of the small pleco like bristlenose or bulldog pleco or a twig catfish.