That is a tough one.
First I thought if each sponsor type was its own reg type, then you can include everything in text widgets. But the sessions are optional, so that won't work.
CSS might work to replace $0,00, but CSS is not available. Yet.
Even if $0.00 was replaced by included, that might look better.Instead of sessions, do you think admission questions may work?To me it looks like you are looking for an accurate head count and not collecting money.And turn off Display Optional Sessions in the registration summary widget.