For some reason the codes would not convert using CB2Crypt and MaxConvert. However Frengky Septo at Gamefaqs pointed me in the direction of some
Action Replay Codes. You should rename this thread and include this link in original post...
I just wanted everyone to post that you can have both Euram and Eresh in their party at the same time. I waited until the very last moment to recruit Euresh and made a save. I then went to rainwall watched the Euram scene, reset my game without saving, and went and recruited Eresh. I turned on the recruit euram code and he actually replaced her on the Tablet (hurray). You can also pick up Sialeeds with no problem. Their are some great codes here. I haven't tested the Cycle thru Encounters code but it essentially makes the random encounters not so random which is awesome if you are both a completionist and a student like myself or if you don't have a lot of free time.
I paid 20 bucks for a codebreaker. I'll check out the equipment that is supposedly not in the game when it comes in the mail.
Update 11/23/2008
Apparently using a code to recruit Euram replaces Eresh's entry on the tablet and allows you to use him in war but he does not appear in your castle which is a complete bummer. I have a feeling Eresh follows the same rules. Sialeeds certainly does but it is to be expected as there is no script for her in the castle at this point.
Update 11/25/2008
I messed around with the the recruit euram and eresh codes and I've made an interesting discovery. Euram and Eresh's recruitability isn't based on whether you've recruited one or the other. This may seem obvious to some but they used a forked event . If you activate one event you deactivate the other. For example I used the recruit eresh code, which added her to my tablet and character list. I then went and recruited Euram. I went back with her in my party to see if the big hole dungeon was open and guess what, it was. The dungeon opens up as long as she is in your party but the boss only appears if you activate her event.
One thing I'm not sure of is whether you can run multiple recruitment events at a single time. If so you could most likely recruit both easily. You would only need a walk through walls code or even better load location modifier code (a code that always makes you return to your room at the castle no matter what doorway in any part of the game you went through, so long as it returns you to a save place). If you had one of these codes you could pick up eresh, walk around the spot where she leave's your party to leave the big hole, walk over to rainwall, recruit euram, and finish up the big hole dungeon, activating the event script for both characters.
Of course this is all conjecture, starting the eresh event could disable the euram event until you abandon here and leave the big hole. I don't think this is very likely as it's a lot cleaner to just keep you from leaving the dungeon and making the fork happen when you "befriend" her or him in Euram's case.
I know a little bit about scripting from rpg maker but nothing about programming or even code building. I know a little bit about the hexadecimal system but clearly not enough. So I won't be making this code but if it's out there and anybody knows about it say something. If anybody knows any serious code makers speak up.
Honestly though, I'm okay with just picking Eresh on the first playthrough and Euram on the second (he really is a great character though).