Your lily of the valley plants are sited reasonably well (shade w/ just a bit of morning sun), altho in our coastal heat, they seem to do best in day-long, heavily filtered shade. Re their failure to bloom, I suspect that 1) they aren't getting adequate moisture and/or 2) the soil needs to be amended to incorporate a LOT of organic material. They thrive in rich, constantly moist soil. If you have good drainage, it's almost impossible to overwater them. They're not the easiest of plants to grow around here, but with a bit of extra effort they give an acceptable showing each spring. And don't forget to water them during the winter if it's a dry one.

As for your irises -- it sounds to me like you really need to divide them. Nothing impedes flowering like crowded, over-grown clumps. Irises love elbow room!