Kim ....
This is probably very much the wrong time of year for you to start container grown miniature roses in your zone. I'd suggest you hold off until next spring after the last frost date for where you garden.
Zuzu is right about getting rid of the the planting medium you get when you buy the plants. That's the first important step.
You are correct in trying to protect the young plants because they have been grown in greenhouses, but growing them indoors won't work well with roses. Roses are outside plants. To harden them off after you have put them in decent potting soil, you keep the plant in partial shade outdoors, gradually moving it towards a spot where it gets more sunlight. (That's why I am suggesting to wait until spring to purchase new roses.) Those roses are a lot tougher than you think.
Another thing to consider when you purchase a rose from a big box store or a grocery store is that as long as they have been in those stores, they have not been cared for properly and you are buying a plant that is already stressed. It doesn't mean it won't make it, but as a friend says, "Those roses are half dead because they haven't gotten what they want."
It sounds like you are watering them correctly. Just hold off feeding them anything until they show new growth. That tells you that the root system is working. When you do feed them, feed them lightly and often. Make sure you have watered the container the day before you feed them and you won't have to worry too much about fertilizer burn.
I have never planted a tiny rose like that directly in the ground and live in a milder climate, so Toni can give you better advice if you want to put them directly into the ground than I can.
I did work in a miniature rose nursery early in my rose life and the owner of that nursery is the one who stressed that miniature roses, or any other rose, are not inside plants.
I hope this helps.
Smiles,
Lyn
