ROM Hack How easy would it be to make a romhack patch of Pokemon Emerald?

[discodance77]

So I was wanting to create a definitive Pokemon Emerald patch for personal use, just to add a few more pokemon to the Hoenn Dex and dialogue changes. Most Emerald hacks are 386 or otherwise over-the-top. I've never made a patch/hack ever before and have absolutely no experience, but Pokemon Emerald was my first ever video game so I want to do it Justice.

Here's what I want to do:
-Expand the Hoenn Dex (or simply national dex from beginning)
-wild location changes
-changes to moves (pp, bp and acc)
-physical/special split
-TM changes (change, say, TM49 snatch for Hydro Pump)
-Dialogue/text changes
-some stationary pokemon
-some gift Pokemon
-giving some Pokemon new abilities
-changing evolution methods/levels
-moveset/learnset changes
-trainer roster changes
-Pokemart item changes
-minor scripting (to add more rival battles with Wally and May/Brendan and possibly Scott and Steven?)
-adding some grass and stuff, new small areas
-changing in-game trades
-adding item balls around the overworld
-adding additional trainers here and there
-certain infinitely rebattle-able trainers (by talking to them)

Obviously that seems like a lot of stuff but I'm also going to try and preserve the original feel of Emerald. This is mostly only for myself, but if I feel the hack is quality, I'll share the patch for it
Having absolutely no knowledge of pokemon romhacking (even what tools/applications to use) can someone help me out or point me in the right direction?

 

[cros107]

XDelta. Works for everything. Never went in depth into Pokemon hacking, so there might be some sort of Pokemon gen 3 specific patch, but if not, XDelta is the way to go.