I don't know how large the angelfish are. They will (should) attain 6+ inches in length (body) with a vertical fin span of 8 inches or more. Assuming they are still young, the tank is currently suited to the pair of angelfish (and the bristlenose, won't impact much) but this is not going to last long. As the angelfish grow a more spacious tank will be in order, or you might re-home them (sell, give away...especially if they turn out to be a bonded pair). So if you want to raise some of the fry the present setup should suffice for a time. Obviously you will need somewhere for the fry, both to develop properly and then be permanently housed, or given away.
To the bonded pair aspect. It is very common for commercially-raised (= tank raised) angelfish to fail in their first few spawnings. Wild angelfish do not do this (unless they are highly stressed). Either or both parents may suddenly eat the eggs. But after a few spawnings, things may settle down, though this depends upon the individual fish. If they bond and accept each other, fine; but if they do not, then they will soon begin squabbling and the result in this small a space will be a dead angelfish. I don't know how you came by your male/female pair, but if they selected each other from within a group they will probably bond. If they were just put together at random, it's hit and miss.
Byron.
