Silk blends are definitely something you should consider -- I've done a shawl of 50/50 wool-silk, and it knit well, had nice drape, and was still easy to block like wool is.

Merino is really soft wool -- but most people find alpaca about as soft as merino.

Merino is wool, so yes, it's just as warm -- most of the other animal fibers like alpaca and qiviut are warmer, but they don't have an stretch to them and not much loft, so they drape more like cotton than wool, which is not bad, it just means you're going to get much more drape-iness with them than with wool.