Nice team you've got there, we don't have enough Ditto abuse teams :d. There isn't much to add since a self sufficient team, but yeah you should follow up on your hunch and run SR & Spikes on Deoxys-D. You get rocks up much quicker that way, which means your team as a whole is harder to deal with from the get go, and you don't have to worry about relying on Tyranitar to use SR (in some cases, you might not get the chance). Balanced Tyranitar is good, but again I think you're honestly better off following your instincts and use a more offensive set. offensive set. Scarf seems like good choice, since the speed is much appreciated and it's an auxiliary check to threats like Latios, Latias, Thundurus-T and the like. Also consider Choice Band is you just want to go ape bananas and SMASH things.
This suggestion might sound controversial, but consider running Jolly max speed Scizor. Not only does this spread guarantee that you outspeed almost every single variant of "defensive/support" Rotom-W (the ones that run 128 speed in particular) but you also get the jump on adamant max speed Breloom, which could save you in a blue moon (if Gengar goes down or ditto is weakened, then breloom is a huge dick to your team.) I want to be clear that this is a minor recommendation, not an outright suggestion.
hope I helped :)