Ok firstly Noibat is until evolved kinda weak and useless so i wouldn't rely on it too much for tough battles until it evolves, if you are trying to win a difficult gym leader like Shelly too in doubles without a full team with one of your pokemon being not very useful you are really dragging yourself down, i dunno if ya got the mystery egg yet but hatching it if ya haven't might net you a decent pokemon to support in this fight, the growlithe you get too has flame burst which if you can use that without rain being present will set Shelly's field on fire and hurt her bugs over time and i think improve fire attacks too so there is that, since you have the Pachirisu you may as well try making use of it's nuzzle leading for parahax and trying to buy time for your other mons to do something meaningful, knowing the abilities would be nice too, if Blaziken has speed boost and can take a hit from both of Shelly's starting too (though she usually goes for rain dance right off the bat with Illumise so only need to be able to take a hit from whoever else is leading) then Bulk up following by blaze kick by make easy work of some of her bugs with speed boost keeping you at a high speed, up to you to keep blazikens health safe, problem with your team, so little info i have on it but already a lot of troublesome signs