The cardiovascular effects of scuttelaria seem to entail a lowering of blood pressure in hypertensive patients and cardiovascular protection against oxidative stress so I can't imagine interactions with MDMA that could be harmful. There is also binding of certain substances in the plant with the benzodiazepine receptors which could mean that it has some anxiolytic effects but this is also nothing to be worried about. There isn't much known about the half-lives of the active chemicals in there since there are a lot but it seems that the data I did find indicates most have a pretty short half life, so if you want to be sure you could stop the treatment a day or so before your roll
Turmeric displays some unpredicatble properties when ingested. The effects are always weak but it has been shown to cause very slight hypertension in some people while in others it produces very slight hypotension. I don't think there is any possible danger because the effects are only very slight. So you could again stop taking this plant a day in advance if you want to be sure
Those were the interactions, you have nothing to worry about when it comes to cross-tolerance. There is none
I searched but couldnt find anything specific.