I'm not big on formal scaping, so these little vases and bowls are more about just enjoying the process for me. There *are* folks who do phenomenal miniaturized creations, but you start having to get into some massive planning and materials resourcing in terms of scaled hardscape and plants for that.
You'll be amazed at how well ordinary plants will do in very small vessels. Originally I figured the low bioload was responsible for the slower/smaller growth patterns--but even with moderate fertilization being added and higher light levels, regular plants just plain grow smaller. Even in a sand capped dirt substrate.
The crypts I use come from a mother plant I bought over a decade ago from a chain store--no label, no idea of the variety. I have used crypt wendtii in my larger (.5-3g) vases, using only the smallest new plants off a mother plant and they've tended to stay small for me.
The only specially small plant I've bought is dwarf pennywort, the rest are all cuttings from my main tank plants: cardamine lyrata, baby tears, star grass, temple plant, various hygrophila, xmas moss, glosso, and, of course, floaters: frog bit, duckweed, red root floaters, various salvinia, spikey guppy grass, and hornwort.
One trick for getting really small growth to plant from a hygrophila is to cut a portion of stem with 1 node, leaving one or both leaves attached. Float it in the small bowl and in awhile (a few days to a few weeks depending on variety and conditions), you'll get a new tiny plantlet and roots growing from the node. Plant that and you'll get small tight growth so long as you don't blast your tiny tank with too high of light intensity.
Oh--and as for the cycling---tiny bioload means tiny need of beneficial bacteria. Even without seeding the substrate the bacteria carried in on the plants will be enough to get things started. Adding a "pest" snail or two right away helps keep it rolling along.