Yes! You can absolutely freeze these and cook them later. I like to cut them out, place them on a parchment lined baking sheet and place in the freezer for 15-20 minutes, then place into an air tight container or freezer bag in layers with a piece of parchment between the layers to prevent them from sticking. Then cook from frozen, they will take a few more minutes to bake than the written recipe.

No yeast does not actually need sugar to rise, so no sugar is added to this bread recipe. Enjoy!

Yes, you can heat the iron skillet before adding the mix – will give you a beautiful crust.
Add a little oil to bottom and side of skillet before heating.

I never preheat my pan when I make this recipe and they have worked out for me every time. You can absolutely preheat your pan if that is what you usually do and what you prefer. Enjoy!

I can’t tell you what went wrong when you made this recipe, it’s hard when I can’t see what you did to help diagnose what could have happened. I have made this recipe numerous times and while the dough is not a soft dough, but more of a slightly sticky dough, it should not be a wet slop and unmanageable. Is it possible you measured incorrectly from the beginning? Did you take the time to knead the dough as well?