I'm new to this forum, but have grown carnivorous plants for a number of years.
You will be very lucky if you don't get many wildflowers (weeds) comming up in your bog on their own, even without nutrients. Peat and sand makes a great media for seeds and spores of all types to germinate in.
Whatever plants you do choose, make sure they aren't vigorous or invasive varieties.
Pogonia ophioglossoides is just one of many wild orchid species that will do well with carnivorous plants. I have had several cp bogs taken over by ferns and grasses of many types here in Florida.
Take your time introducing non carnivorous plants to your garden, and you will be better off in the long run.

Good growing,
Steve

Pogonias can be difficult, but there are other bog orchids that do pretty well with sarracenias. I grow Calopogons, Spiranthes cernua, and Habenaria (Platanthera) ciliaris in my bogs with pretty good success, and none of these will take over. I spent the weekend weeding out Onoclea (sensitive fern) and hayscented fern, so I can't recommend these. Several Zephyranthes species do really well in the same conditions - alatamaha, candida, and flavissima, in particular have been really successful for me. I am cautiously experimenting with gold Lysimachia as a groundcover in the bog - it looks beautiful, but can be invasive. I'm hoping its low growth will keep it from conflicting too much with taller species such as S. leucophylla and flava, but I'm introducing it slowly, just in case.

I think some companion planting can be helpful for sarracenias in order to provide support and protection for new growth (in nature they grow in conjunction with reeds, grasses, etc.), but it's hard to keep a controlled balance in that kind of culture.