I love this change, but I was watching the Yogs play this and noticed due that due to the world congress these boosts can be effectively rendered moot by the decision to suspend all points to a certain great person and I was wondering if it's possible to have the world congress's decision be tweaked to only reduce great person point by a percentage, or if that isn't possible at all?

I think so, yes.

Does Tamar get these bonuses in addition to the golden age bonus when she gets a golden age?