First off, I’m very happy to hear that you’re looking to track multiple different sources for conversions and effectiveness. Good hustle so far!
To answer your question, both of your scripts should work just fine on the same page. Basically, if someone clicks from a Facebook ad and has never clicked his Google ad, it should only trigger the Facebook conversion pixel.
What’s great about this setup is that it gives you the freedom to track individual campaigns on different platforms, while at the same time collecting all of your lead data in one place. If you want to take this a step further and see _which traffic source your leads came from in the lead data, you can simply add a URL parameter to your links and track it with a hidden form field.
I’m sure there are even more creative ways to track separate campaigns in Unbounce. If anyone in the community wants to share their approach, please feel free.