I still have a good amount of non-native plants in my landscape, but I've decided to plant just native from now on. Without significant research of each and every nativar out there, and more that are introduced each year, there's just no simple answer to your question. Nativars have been known to spread or interbreed with local native plants displacing native flora. Sometimes the nativar can support local species, but sometimes not. It's a crapshoot. By planting naturally growing native spieces, it assuridly eliminates any possible negative impacts.

I have Canadian elderberry in my yard. I consider it to be one of my most beautiful plants. Cultivated in the garden, it's much more stunning than in the wild IMO. I think the white flowers and red/black berries against green leaves are prettier than the dark leaves with pink flowers of the cultivars that you're considering, but again, that's just my opinion. I can appreciate you wanting a plant that gives a punch of color to an otherwise green landscape.

Having said that, I often suggest to people that they not plant burning bush because it is invasive. They say to me that it is not invasive in their yard. I tell them that the birds eat the fruit and spread the seed to natural areas. They say they have never seen fruit on their plants. I say that the fruit is inconspicuous. My point is, you just don't know if the plants in your garden are invasive by simple observation.