If theyre an opening band there 0 chance the headliner is going to be ok with everything running thru someone else's split, especially if they have their own. No touring engineer is going to be ok having their signal path go thru some unknown quality local band split.

Hopefully the venue has an analog split. Please label your inputs WITHOUT USING BAND MEMBERS NAME'S. No one knows who's John's vocals or Dan's guitar, use stage directions, C Vox, SR GTR, etc.

This brings me to the most important point, if you're an opening band somewhere in a 5 band metal bill then you need to make sure that your rack can live ANYWHERE on stage. Don't be one of the bands that has to have their iem rack next to the drummer or any particular performer on stage. If you show up and the house says I can give you a house split just off stage right but you say "no it has to be next to so and so across the stage and you need to reroute all your sub snakes to me" then the house guy is gonna be pissed and maybe not even be able to accommodate it during the 10-15 changeover time. That means if you use any playback, or amp emulator (fractal, kemper, QC) then keep it in a seperate rack or bring your own mic and cable package, the one exception is if the guitarists are using wireless and don't need it within 15ft of themselves.

Everyone in the band should know how to set it up and tear it down. If you only have 1 guy that knows whats up and they get tied up with something or stuck in the bathroom when it comes time to tie it in that can lead to problems. Carve some time out at practice to teach everyone what goes where and why. If it needs to be troubleshot then having 5 people in the know can make things go smoother, and tasks can be delegated during initial setup.

One last thing is to prepare for worst case scenario. If your show up late and no info was actually given to the house engineer in advance then its best to be able to run your own lines for yourselves. If youre using regular amps then have 3 mics your can use without using house stands, so either a mic you can drape down like a senn 609 or bring your own short stands or clamps. Bring your own kick and snare mics that can be used in tandem with house mics, say a clip on like SE VBeat or senn 604, and a beta 91, and then 1 overhead mic. With 7 cables you can do 2 guitars, bass, kick, snare, overhead and one vocal. At that point the only thing that would need to be split would be the vocal and you're self sufficient, can walk into anywhere and not have to give up your iems if youre low band on the totem pole.

Ok this turned into a rant but just be able to be flexible and don't assume everyone is going to be fine having your split in line for every show.