It is quite normal for a squash or gourd to produce only male flowers initially. The females will appear later. Cutting off the males is not likely to speed the process. Since the squash/gourd plant will produce relatively few female flowers during the life of the vine, perhaps the early appearance of the males serves to train pollinators to be there when the females open.

I'll recommend Moondance for a white floribunda. It doesn't last a long time in the vase, but it has so many flowers that it is easy to go cut a new one every few days. It smells really good too. I didn't think Sunsprite made a good cut flower. It just doesn't have much of a stem. It does have a lovely bright yellow color and a strong lemony fragrance so I still like mine. I'm not certain mine lived through the winter but that might be where I have it planted. I won't know for sure until I prune though and that won't be for a few more weeks.

Depends how big your cannas are when you put them out. If you are planting rhizomes, you can't keep them soggy until they get some leaves on them or they'll rot. If the plants are already started, it probably would work fine, although I've never grown mimulus.

Roguchi is one that was bred specifically for the cut flower trade in Japan if memory serves me correctly. Others in the photos I have posted (one photo didn't show up-must have copied the wrong tag from my photobucket account) Proteus, Piilu, Helios, HF Young, crispa, glaucophylla, Petit Faucon, Star of India, Duchess of Albany (which you correctly picked out!), Sputnik, Huldine, Betty Corning (great scent), and countless others. I have probably at one time or another used blooms from all of the clematis I have now or in the past as cut flowers and that is well over 119 different varieties.