sd lo terrakion is the only thing you seem hard pressed on.. so the only solution is possibly lowering its switch in chances. maybe a will-0-wisp on heatran > protect can do the trick. another option you could do is psycho shock > psychic on mew so it lures in latias and maybe LO latios (not specs). you can pierce through latias' defenses in particular and possibly give you an easier time with it.
last option.. you could speed bump tran with 16 spe or something to outpace those bulk up breloom before they spore you. pretty cool team still.