Is it possible to programmatically get signals from a protected strategy?

In other words...if I wanted to develop a strategy that integrates signals from other strategies that aren't open source, how would I do this?

If the signale are exposed, then yes. It's not always the case, you should check with your vendor.

Suppose I can't reach the original developer. Is there a common way to check if any signals are being emitted?

I'm fairly new to programming Ninja, so my apologies if I'm not using the correct terminology.

ShrewdBiz 

Suppose I can't reach the original developer. Is there a common way to check if any signals are being emitted? I'm fairly new to programming Ninja, so my apologies if I'm not using the correct terminology.

Yes, in using the Strategy Wizard.
When you're in "Conditions and Actions", add your protected indicator, and check what you can get in the "Plot" field.