I haven't looked at my TCG mod in ages. I still have all my files for it, which you're welcome to. I did a bit more to it after the download I provided, but I have no idea what. The download for (nearly) all my files is here: https://www.mediafire.com/?wn64c937esopgwu
Looking at it again, I'm impressed that I did so much with it. If you need any help, let me know.
I found out why it was showing 4 1/2 tiles in a 320x288 sized game. In Crystal version, the camera is off by 1 tile to the right, or in this case, half a tile (16 pixels) to the right. I would like to do this, but have no idea what to edit in the Map_Scroll Script.
Struggle - Try looking at its function code. I'm pretty sure I also made some other changes to the scripts to make it work, but I really can't remember what. I would suggest you just copy across the battle scripts in their entirety, because it's easier (assuming you've made no changes to them yourself) and is certain to get Struggle to work.
Underwater transfers - The def is new and mentioned by name in the change list. That's all there is to it.
Alright, I'll definitely upload it once it's done on the wiki. I left a couple of suggestions in the thread but, as you said, they are not essential (Ghost tutorial like the one desbrina made and I also made a suggestion of an event where the legendary pokemon can dodge a ball similar to the original RBY games.)
You can always put it in a tutorial on the wiki. I don't really want to add things to Essentials unless they're, well, essential, or at least will directly contribute to most games. Honey trees just seem a bit too optional to me.
I'll admit I'm biased here. I've never used a honey tree, and I'm not that keen on them. I also don't think they would work well as is, because Essentials games would need to be played on a computer and they're less portable (meaning players may not be able to get the timing right, leaving them frustrated). I know berry trees are the same, but they're already in. If there's enough demand, though, I can incorporate your tutorial into Essentials later.