First, your 'sprouts' or any seedling grown Japanese maple cannot be a named form like 'Bloodgood'. Named forms can only be propagated asexually, by grafting (most common) or cuttings (much less common and harder to do). Seed grown Japanese maples are just examples of the species, Acer palmatum. Period. These can be very variable in leaf color and shape, sometimes looking very much like the parent tree and othertimes not at all.

I can't tell you how much or how often to water but you want the soil to stay just moist - not wet and not too dry. You should have some drainage holes in the bottom of those cups :-) And in zone 8, it is never too cold for Japanese maples unless you are trying to grow babies like these in those cups outdoors over winter. It is best if you have one seedling/sprout per cup........once they reach about 6-8 inches tall, you should repot them in a larger pot with good potting soil. This time next year you can plant in the ground.

Thanks so much, you have answered all I needed to know and you taught me somethings too lol