1056 or 1098 would be my two choices. You'll end up with a little less attenuation with the 1098 but being an imperial you can utilize some corn sugar to help dry it out. The only reason I say 1098 is bc I'm partial to English yeasts in pale beers
Negative. Two packets, either rehydrated or directly pitched. I just brewed and pitched a beer just like this a couple days ago - 5.5 gallons, 1.087 OG Black IPA. I pitched two packets of BRY-97 (first time using it). Tasting notes would be useless, though, as our recipes are probably vastly different, and either way my fermentation got way too warm for several hours, so it's probably not going to be a very good representative of what BRY-97 is like in ideal conditions
As for why not to make a starter: there are way more cells in a packet of dry yeast than liquid yeast, and it's engineered to be at its best pitched as is, rather than making a starter.