Please avoid necro (reviving old topics) to ask questions, create a new topic for it instead. Also if you have many questions and they are somewhat related, ask everything in the same topic.

Usually you'd set the timer to 999 in mugen.cfg, but since this is Ikemen, the equivalent to mugen.cfg is config.json in the "save" folder. IIRC, you need to open Ikemen GO at least once for these files to appear. You probably will want to change the timing in fight.def from 60 to 6, else it will take forever for the fight to end (it will be 999 seconds instead of 999 deciseconds (one tenth of a second)).

For the select.def, are you sure you're editing the right file? Are you sure the characters are in the right folder? Try filling the select.def with randomselects so you can se the select grid better, then add characters in small portions.

To install a screenpack is the same thing as MUGEN, but instead of mugen.cfg, you edit the path to the screenpack in config.json.

Edit: Also, don't delete your posts, especially after all the work I had to put them together in this topic. I'm restoring them.