Ok, my thoughts:
First, Scizor can really hurt this team. If it gets a swords dance boost in, then that could spell certain death for some of your team. I might consider using Magnezone or Magneton over Jirachi, so that Magnezone can trap and kill (or heavily damage) Scizor with Thunder. Also, Starmie can pose a problem to some team members, once Ferrothorn goes down, that is, because of its Rain boosted Surfs and super-effective attacks to your team. A solution could be to have Choice Scarfed Magneton, as it could then revenge kill Starmie and trap Scizor as well. (Scarfed Magnezone is slower than Starmie, whereas scarfed Magneton is not).
Also, Blissey could be a problem to this team, once certain team members (Ferrothorn and Terrakion) go down. I'm not sure of an exact solution for this, aside from being careful. You could maybe put Psyshock on either Jirachi or Latios in order to hit Blissey (probably Jirachi more than Blissey; with its CM subs, it can beat Blissey).
This looks like a decent team; maybe 'standard', but still decent. I may have more thoughts on this later.