This is a pretty simple patch that adds the one thing DWM2 was missing. Namely, the last few monsters. Dimensaur, Lamia, and Kagebou are obtainable with this patch. Wonderegg and Watabou no longer require linking. Note that because the promotional giveaways are certifiably deadly, they've been put in breeding chains you probably won't complete until post-game.
The new breeding combinations, aka the only important thing, are detailed in the readme. This patch works for both versions (Cobi and Tara).
This would be more awesome if we can get both keys at the post game.. It really pissed me off when I only got one and couldnt get the other lol. If only I knew how to hack it in I would lol.. If you could can you make that happen? This would surely be a treat :)
Sadly that's the one thing I could never get a lead on. Can make LastLord keys more common, add all the monsters to the game, change all the battles, add more items, change the skills, etc but never could get those link keys together in one game. ;_;
If it's any consolation, those keys only unlock generic boss rushes. So at least you're not missing out on one of the more interesting subplot keys.
I was able to find the value for the key rewarded by the old man (Brawn/Baffle). It is buried in a script. My hack changes this to the Lonely key. I ignore Brawn, Baffle and Soul because there are no monsters to catch.
Do you have the address? I may not be hacking the game actively but I'd be interesting in adding that to the ROM map on the modding wiki.
EDIT. Never mind I see you've been all over the wiki already lol.