According to the Wikipedia article on caffeine, its solubility is drastically different between room temperature and boiling (2 g/100 mL room temperature to 66 g/100 mL at boiling). I assume this means it's easier to get caffeine into boiling rather than cold water, but the drastically longer steeping time may counteract this. It's worth noting that the solubility is far higher than the actual amounts of caffeine that's in coffee.
Farther down the page it mentions caffeine per liter of liquids like coffee (386-652 mg/L). If you can find similar information about cold-steeped coffee, it might help.
It IS the roast that is the difference. The only real difference in the beans is that some beans taste better at a higher roast than others, so they are more appropriate for espresso. Your Italian grocery coffee company may be using the espresso label for marketing purposes, but in general, espresso coffee beans can be the same beans that are used for "regular" coffee, but roasted to a French or Italian roast level, which is darker than City or Full City.
Since the advent of Starbucks, many roasts are much darker than they used to be. Dunkin' Donuts coffee, which is a Full City roast, used to be the norm, but now a French seems to be what you can buy.
I roast my own coffee and take it to just into the second crack which is, generally, a Full City roast...a point where the character of the coffee predominates rather than the flavor of the roast. There is more information about roasts at Sweet Marias where I buy my green beans, and reading through the site will give you way more of a coffee education than you probably ever wanted.
So, yes, you can use the coffee you have to make brewed coffee. It will probably be roastier than you would normally have, unless it is just a marketing ploy, in which case it will taste normal. Consider how long you have had this coffee; if it has been shelved for a while "normal" probably won't be all that great, since freshly roasted coffee is, generally, way better than old coffee. But as long as the oils aren't rancid, it is more likely just going to be bland.
Best Answer
I've been using a Toddy for about two years now. I have found that you can get a plenty strong concentrate with only 1/2 pound of freshly ground coffee steeped in filtered water (like in a Brita) for just short of 18 hours. Beyond 18 hours the grounds become waterlogged and the same elements that produce the bitterness found in hot brewed coffee start to come out. 12 hours, though, is barely enough to get the flavor out. At only one or two hours, I can't imagine that there would be much flavor at all. If you use a Toddy, you will find that using a finer ground will result a very cumbersome, frustrating draining process and/or sediment in your concentrate. As to the caffeine, I believe you will find that the matter is undecided. Someone needs to conduct an experiment with well defined parameters to really figure it out.