To completely skip the world map in FE8, you need to have the scripts for the pre chapter scenes AND the scripts for the world map scenes.
When you have both, you essentially then need to do the following:
- Remove all the pre chapter text. If you don't do this, the pre chapter text will display on a black screen before the chapter begins and you would have to proceed through it and stuff. I usually use this code to do that:
ORG ??????? //Offset of the chapter's world map code
You move to the chapter using MNCH
You have the world map code for the chapter (not the pre intro one but the one from the script that comes with the event assembler) use event code like this:
ORG ?????? //Your offset
_0x1020 0x1 //Don't touch
_0xC360 0x0 0x0 0xYY 0xZZ 0x0 // _0xC360 0x0 0x0 0xYY 0xZZ 0x0 YY = main lord. ZZ = just completed chapter
_0x8540 0x0 0x0 0x0 //Always have after 0xC360
_0x8540 0x0 0x0 0x0 //After load map
_0x9340 0x0 0xXX 0x0 //Silently and instantly load world map location. All three XX's should be the same. Remember that this XX should be the world map location offset and be the same location the chapter occurs in vanilla FE8
_0x9A40 0x0 0xXX 0x0 //Sets WM destination
_0xA640 0x0 0x0 0xXX //sets your position to that place
You'd need to know more about world map events to get further into this process.
The only chapters you can safely jump to using MNC2 are both versions of chapter 12 and the first part of the final chapter I believe. Maybe the tower and ruin chapters as well, but those have other issues with them so I don't usually work with them.