Oh well, I'm happy you enjoy Reborn!! I have a couple tips for your team. Don't use them for a regular playthrough, I'm only telling you these things for online play
First of all, be aware that Naganadel is by far the most destructive pokemon in the game. The ideal set would be Nast Plot, Sludge Wave, Draco Meteor and Flamethrower/Heat Wave. His goal is to get into someone who can't threaten him directly, like Venusaur, Clefable or many others, force them to switch, set up a Nasty Plot and destroy entire teams thanks to the beast boost. The best item is usually the Dragonium Z, altough I've seen also focus sash and poisonium Z being decent. Tyranitar is another one of the best pokemons in the game. Usually, people play him with the Assault Vest (AV) as the special defense boost makes him able to resist a Z-Draco Meteor from a Naganadel after a nasty plot and ko in return with Earthquake. That's crazy, but true. If you want to play dragon dance, instead, use these moves and leftovers as an item. Speaking of Togekiss, instead, you can play defog and roost instead of dazzling gleam and aura sphere. They deal no relevant damage and you want to have team support while keeping Togekiss healthy. For your Excadrill, I would suggest a life orb, but remember that pulling off a sweep with sand rush is not an easy task. Salamence is instead someone I don't really like... the Z-crystal is not so good with an 80 base power move. Lum Berry, Leftovers and Life Orb are good items. And please, use Fire Blast or Bulldoze instead of Brick Break
The last step is finding a mega evolution, that's your choice... my suggestion would be Mega Kangaskhan, who is very well rounded and has a nice bulk, your team will need it. Have fun!! Hope we might have a battle one of these days