fireredlugia

You should be able to do it before inserting the CFRU. If I remember correctly, it's just a routine you callasm from a script.

You can add the raw assembly in the assembly directory, or convert it to C code. As far as I know its standalone code so it's more a matter of understanding asm/c to add it than anything to do with the cfru specifically.

You mean. Pre-battle mugshot or mugshots shown during regular dialogues?

if it is overwriting any important code/data in your rom you'll get a crash, which is probably what happened.

I'm not sure where the patch came from, so I won't be able to help you, unfortunately.

page. 127. Special 0xD1 sets up a follower and describes what you need to edit.

The documentation explains it quite thoroughly.