I ran BR7ef plugs last year with Vortec heads. Ran great the whole summer.
There's basically no way around a Cold Start on E85. The amount of volume E85 has makes it hard to start when cold.
Yes, it drives cold just fine. I'm running old fast system, so I look at lambda and tune on the gas scale. It idles around .95 and makes power around .85. Idles with 30 degrees and power with 20 degrees.
Sometimes cold cranking can take a little longer with E85, but it should be fine once started. I would suspect you have another issue, but a datalog might help zero in on it. If we need to change something in the tune, thats not a problem.