Is it safe to take a prenatal vitamin along with a B12 vitamin and cranberry supplement every day?

Sure. These may increase your appetite slightly, but i see no reason for concern. You may want even higher Folic Acid supplementation at 1-5 mg daily (pnv have 0.4-0.8 mg per pill) in order to prevent preterm birth, fetal cardiac and neural tube defects.
Perfectly safe. If the prenatal vitamins are good for pregnant women, you should be assured that they would be good for anyone. And there is no interraction between cranberry supplement and b12. All very healthy for you.