Disruption Delay is highly recommended (sometimes arguably mandatory) for all Megas from Mawile to Mewtwo Y, that alone makes them much easier to deal with since Disruption Delay lasts so long. +5 Turns is always useful too, and with the lack of disruptions for awhile you might be able to afford not using Mega Start right away and save some coins. Disruption Delay itself is only 1500 coins so farming a bit on Stage 37 (Meowth) can get you those coins if necessary without too much struggle, especially if you can get the 330 coins each time.
As for Mega Aerodactyl you can reasonably finish it with no items thanks to breakable blocks being way less obnoxious disruptions than freezing things constantly. Blastoise and Milotic are very useful here for Stabilize+ and Kyogre's Rock Break also comes in handy here, so any of those are useful. Mega Lucario is also fantastic here, though Mega Blastoise works here too if you don't have Lucario. If neither are options then I guess there's always Mawile, which is a lot better than nothing. Mega Aerodactyl is no pushover but I'd say it's definitely a generous step down from the mess that Mega Glalie/Gengar/Mewtwo Y are.