I'd agree that having an awesome team gives you a lot of other advantages, and actually FP is a huge opportunity to build that team for start ups. FP tends to attract the kind of people who make up a great team.
Yes, absolutely. It's amazing how overlooked this fact seems to be, by many. Languages aren't that hard to learn, so excluding the really awful ones (e.g. Java for anything other than code that has to be on the JVM and has to be fast) the "familiarity" aspect is minuscule. Programmers learn new languages quickly. What does matter is the community and the quality of programmer you'll attract based on the tools you use and the signals that your tools send about who makes decisions.