Well the first step is to actually figure out which Pokemon you're having problems with.
My suggestion is to go out into the wild and catch two Pokemon. Place those two Pokemon in you party along with two of the Pokemon you wish to bring into random battle. Let's call these desired Pokemon, "Pokemon 1 & 2". If you get through, Pokemon 1 & 2 aren't the problem so swap them for Pokemon 3 & 4, etc. If you don't, one of your desired Pokemon is illegitimate. Remove Pokemon 1 at this state and retest.
If you get through now, then its Pokemon 1 that has problem. If you don't, swap Pokemon 2 for Pokemon 1. Go back and do the same. If you're good then Pokemon 2 doesn't have problem and you've isolated that it was Pokemon 1 with the problem. If you don't get through, then they both have problems.
This whole process for a party of 6 takes about 10 minutes so it's not that time consuming.
Once you've isolated them, go ahead and pack them into a ZIP file. Attach the file and I'll debug them, telling you what's wrong with them so you can learn from your mistakes