BDB,
You might ask your supplier how late in the year they will stock BG. They should know the local rule of thumb.
FHMs start spawning in the spring at around 64F (plus some other factors). If you put them in now with some spawning habitat, they might sense that the waters contain zero fry and try to pull off a late spawn. (Since the water is still "warm" to them, although the daylight is waning.)
I deepened an 80 y.o. groundwater pond last fall that went dry during the drought. I just did it to water my wildlife, but I was amazed at how quickly it filled with invertebrates, water plants, and FA - with no connection to any surface waters.
If part of your swamp water or swamp sediment got incorporated into your new pond, you might be surprised at how quickly new life will fill in their newly available environmental niche. The FHMs also need something to eat, but I suspect things within their diet have already started growing in your pond.
