• Celebrating false religious holidays.
Celebrated Thanksgiving with my "worldy" relatives a couple years back. Check.
Participation in interfaith activities:... sharing in false religious songs and prayers.
Went to my "worldly" cousin's wedding - at a church - some years back. Said "amen" to the preacher's prayer. Check.
Deliberately spreading teachings contrary to Bible truth as taught by Jehovah's Witnesses
Not that JWs teach bible truth or even that there is any such thing, but no, no *spreading* of contrary teachings... yet. Uncheck.
Causing divisions and promoting sects
No outright sectarianism, but whenever my JW parents have issues with being treated unkindly by the elders, I do my best to fan their resentment. - I'll give myself 1/2 point for that one. 1/2 check.
Continuing in employment that makes one an accomplice to or a promoter of false worship
Nope. Uncheck.
The practice of spiritism
Runecasting. Check.
3-1/2 out of 6. I'd say that qualifies.