Q: When you have 2 Iron Core Chimera in the grave, can you return both copies to hand in the same draw phase?
A: Chain 1: Iron Core A activates, Chain 2: Iron Core B activates. Resolve, Iron Core B returns to hand, skip draw phase. Iron Core A fizzles off.
Q: When you have no cards in deck, can you add Iron Core to hand instead of drawing?
A: No you cant
Even though there isnt a direct ruling on Iron Core Chimera and skipped draw phases, I pasted the above 2 taken from here which explains how such cards work. So some reverse thinking will get you to your answer.
Analysing the above questions, the cost to return Iron Core Chimera to hand, is that you must skip your draw phase. Therefore, if you have no cards left in the deck to draw / you have no draw phase (Due to Reckless Greed, etc), you cannot activate Iron Core Chimera to hand.