Can minced garlic be substituted for whole cloves when roasting?

Nope. As stated already minced garlic will burn.
Roasted whole garlic cloves are the most delicious thing probably ever, so the extra two and half minutes peeling the cloves are worth it. Although you can certainly buy peeled cloves now

Generally recipes call for roasting a whole head of garlic; it helps to cut off the pointy end and put that cut-side down on an oiled baking dish. Trying to roast minced garlic per se will not work; you'll end up with burnt garlic.