Sweden is likely not part of pact. If he is not then declaring war on him will not trigger defensive pacts. Usually pacts, even at 100%, will form only with religions you can potentially Holy War (adjacent borders, two sea zones away.)
So if you do not border the Manicheans in Mongolia, Even if you conquer 2\3 of the world they will not be in pacts against you.
I was Roman Emperor and India never formed a pact against me until I took Persia and began to border them. As mentioned the Manicheans in Mongolia? Still no pacts against me.
Great Holy Wars (Crusades or Jihads) will also not trigger pacts. Though same religion foes will likely join as per usual.
Two things raise threat faster than any other. Vassalization and Holy Wars. You can conquer a kingdom through a claim and it would give you about as much threat as holy warring/vassalizing a duchy. Try to avoid doing either.