Question:
Let's say Dash passes Litecoin and is fighting for 1st place with Bitcoin, would it help or hurt Dash if it forks away from Bitcoin and become it's own separate coin?
First, it won't happen for a long while. There is way too much VC money invested in BTC > read, tons of people working on the Bitcoin protocol and connecting with it.
Having said that, second, staying closely aligned with Bitcoin means its easier to make the switch. The one that becomes the market leader gets to set the pace on development work.
It would be no different to developers having to make choices about IOS vs. Android.
One thing is for sure, all the above means that adoption for Monero is likely to be a pipe dream, at best.