Here's my thoughts on this: If you mulch the area well with newspaper and straw, and plant the seeds so the vines will have lots of room to grow, this would be an interesting test.
Don't plant too many seeds, just one package should produce several gourds. As for the shapes, the birds don't care what the shape is as long as they can make it their home.
Another concern is the plan to harvest in late September.
Here in Illinois, we usually harvest in late October or November. The main thing is that the stems are brown and dry and the gourd is showing signs of the end of season shut down. Of course, the gourds can be left on the vine through the winter season for curing too.
All in all, I think this might work. Of course, if your mom decides otherwise, she can always pull the plants up. Or, she might enjoy watching the vines and gourds grow...
.....who knows?

Good Luck,
Jan

In my mulched bed (wood chips), the only thing I do all summer is kick them out of the way of the lawn mowing guy. I have an agreement with him, DH, their in the bed or he mows them down. I could get more gourds per plant if I did some hand fertilizing, but I forget to do it. Never water them either.

Well, I tried to germinate the seeds and after a week got only a couple with any activity. But I amended the soil and planted the starting plugs to do what they will. Thanks for the advice--I may post again to this thread if they do anything, which I suspect they in fact will. Cheers!