Fedorajoe, at this point, whether it's identical code or not, what Grimoire's presented you with here would yield the same result as what I would have come up with. Geez, does this guy ever sleep?

LordGarmonde, it's safe to use any space in the ROM, as long as you KNOW you won't need it for anything else. Whatever code or data is/are right before that, any chance any future modifications might necessitate using that space? If not, you're good to go.
Another thing to consider, though, would be the limitations of jumping and subroutines presented by picking an arbitrary empty space. You're planning on using space in the LoROM 0F's. That means any JSR or JMP would have to reference another offset within the 0F's - that's the way those commands work. They have sister commands, JSL and JML, which allow you to specify a long address, but those require an extra byte to use. Also, the return code from a JSL (RTL) is different from that of a JSR (RTS). If you jump to an existing subrotine using a long address it will crash the game if it tries to return with an RTS. There may also be references that are impossible within a different chapter of ROM (block of 0xXX0000). Some or all of this might not matter at all depending on the code you're planning. Just some things to consider.
You would reference the in-game (LoROM) address, by the way. Those are the offsets the game recognizes. We tend to speak mostly in ROM addresses because those are universally recognized by hex editors. An unfortunate and highly obnoxious (imh and completely irrelevant o) but unavoidable fact of hacking...