Very good observations Thomas, part of the "three sisters" planting setup is that you bury fish first, build a mound over the fish (one for each plant your going to put in right away which is the corn), then you plant in succession, so each comes up at the right time for it.
Many of the people I know who have tried the method plant all the seeds at the same time, this can create problems since the corn, beans and squash all compete for
water, nutrients and sunlight at the same time. That is not how companion planting was carried out by the people.
We would plant the corn, it would come up and start growing, once it was about a foot tall we would plant the beans close to the corn stalks.
When the beans were starting to twine around the corn stalks we would plant the squash seeds further out so everything had space to grow as it wanted to grow.
There is not problem at all with only having pairs if that is what works best for you, then that is the way your
land wants to be planted.
Squash bugs are a problem and they will attack plants that are not in the family. To get their numbers down you can remove the leaves with eggs and burn them, you can pick the bugs and drown them in soapy water and you can turn the soil in mid winter to get a kill on the hibernating adults.
Changing where you plant each year can help but we have found that the adults just seem to be able to locate the new area, so we do all of the above methods to reduce their numbers.
I'm still looking for the right predators,
chickens seem to be a pretty good predator but they tend to decimate the plant at the same time.
Redhawk