Don't know the rules in your State--I would be fine with subpoenaing someone directly even if they had a lawyer, though I probably couldn't TALK to them without the lawyer's permission. My guess is if that's what they told you, it's true.
I hate dealing with witnesses who have their own lawyers. It's totally unnecessary unless someone is on iffy legal ground.
I'm sure you are gonna be feeling the stress until this is over with. Try to distract yourself if you can--I think the more you focus on it the more nervous you will be.
Remember what I said about letting go. The process is in motion, and if you try to over-control it you will only be messing with your own head. Try not to overthink it, just do what you have to do, and everything will turn out OK.