pianoguyy

But I think most people would agree, and the reset link alluded to it, that flashing the latest firmware, even if you already have it, is a good thing to do before a global reset. 

Like you said, apply one (or more) or the many eq's (or other effects) to the exp pedal. 
 
The Pod's exp pedal can control many options at one time, even in opposite direction. And values don't need to run 0-100, you can apply random values like 24 to 61, or 98 to 87. So, unlike, let's say, a wah pedal, you have a much greater flexibility. 
 
I am hesitant to tell you exactly what to do because we don't know what your input source is, nor what you exactly want out of it. Meaning, a keyboard has many more tonal options than a guitar does before we even to changing them with outboard effects. And if we told you to add a tremolo to get that pop-pop-pop sound, you may not want that part. 
So, really, its all up to you. 
 
But, like I said, it is quite possible that the 500 is not the unit for you. 

That sounds like a phase issue that is due to not being properly plugged in. 
 
Test it using your patches.
The next time you have this "reverb only" issue, make a patch that is panned completely left and completely right.
I bet it will sound normal. But as you pan the left and right to be more centered, it will start to phase out.
 
And if that is the case, just buy a new adapter or headphones.

Yes, you can use both at the same time. But to answer the question as it was asked: 
No, you cannot simultaneously use one patch for vocals and one patch for guitar. You would need to make one patch that uses them both at the same time. 

I didn't mean that was my 'real' real name. I meant it is my real internet name. If you ever run into a pianoguyy online somewhere, more chances than not, it is me. But, again, I don't actually converse anywhere anymore. And because web searches have become so inclusive, I have done my best to remove my real name from being associated with my web name as much as possible. 
 
 
And holy smokes, I know this is L6 which is owned by Yamaha, but that is actually an insult to me. My stores carry the far superior Kawai pianos. 
Here on the board, because of the ownership, I try my best to refer to things as Brand K and Brand Y, or Brand R and Brand L for the digitals and organs, that way nothing I say can be assumed to be any kind of a insult.
 
I am not trolling the pages looking for ways to put out disparaging remarks about Brand Y just because I am a Brand K dealer. No, I say disparaging things about Brand Y because I say disparaging things about Brand Y. I deal with Brand K because I like Brand K. One has nothing to do with the other. So, I at least try to keep it kosher by not using names. 

First, if you are using an amp, you need to turn off the amp models on the pod. A Marshall will never sound like a Fender. I know some people disagree with me and will use models through amps, but ultimately a Marshall will never produce a Fender sound. 
 
But, probably more important is: 
You need to make sure you have your settings set properly, and you will need to tweak your patches. 
For example: is it set for direct/studio or set for combo. It makes a difference. 
You patches need tweaked for that setting, and retweaked for your new sound source. 
 
Think about it. How long have you spend on your pod, getting it to sound just how you like it. 
And then you go and change the sound source. It isn't going to sound the same. But you can make adjustments just like you did when you first got the unit.