you do what you think is best for your child. don't let anyone interfere with how you want to bring him up. she has all the right to try to indoctrinate him into her religion and you got the same right bringing him up in your religion or non-religion. the problem is, she'll be talking bad about you all the time and you don't want to do the same, it's not healthy. football team would definately be a good thing, as he'll have much contact to normal people there. celebrating birthdays etc. is good too, if he one day refuses to join in because of some guilt trip, ask a lot of whys and don't accept a "it makes jehovah sad" answer.
it's hard to keep the balance, having one parent say the completely opposite of the other isn't really good for a child, but it's her fault really, actually not even hers but the organization's. anyway, even if he'd grew up in a 100% JW household, there's a >60% chance he'd leave that religion. offering him a normal life and not being judgemental while still talking about serious topics, showing the flaws of the watchtower in a subliminal way, will give you good odds. i hope.