Hi my name is Skys also I also am working on a bug mono, I'm around the point just before facing Luna but it's kind of an off and on thing so i don't play on it that often.
But anyway this is what i picked up through my playthrough. I HIGHLY recommend you make your self an exception and train up a bibral to gt that litleo for headbutt because the pokemon (burmy, combee, and pineco) you get from it are very very helpful. Probably the most helpful is female combee though it is rare when evolves into Vesqiquen it can relearn destiny bond, slap a quick claw on it which you get from wild meowth and it will get rid of pokemon that would destroy your team like Chattot, Heather, Chandelure, Steelix, Chattot, did I mention Chattot?(edit, just realized the move tutor was moved to after the fifth gym, vesviquen s till a good pokemon but won't be as useful without destiny bond) Burmy provides good typing with its ground/bug(great pokemon for Julia) or steel/bug and pineco becomes a great physical wall though it hits pathetically. I'm a bit iffy on the wurmple line beutifly has a great special attack but is pretty slow(base 50) dustox has good special defense but everything else is rather lackluster. Some things you have to look out for later on, Chattot is going to be horrible and s a big reason why you need a steel/bug or pokemon with sleep powder, i'm not quite sure how to beat Cal without going back a few eps and getting a dwebble, and Shelly is going to be the bane of your existence I fought the old version and it took me +35 tries to beat her. Your main problems are gong to be the anorith, scyther(not sure if she still has), yamega, and to an extent bugsy. The new Shelly lead with Illusime and anorith, ilusime sets up rain and anorith with swift swim id going to spam rock slide, scyther has its technician wing attacks, yamega has ancient power and you can't outspeed it because of speed boost, and bugsy is going to confuse you and heal all your damage off with moonlight.
Bug mono is definitely one of the more challenging monotypes I wish you good luck and if you need any help just message me.