I'm a little bit confused. Is this a venue that was offering a package? If there weren't enough RSVP's, so they moved the group to a different room, I would still expect the same package out of it.
You state initially this included a meal and nonalcholic beverages. Next you're worried about paying for alcohol (that you won't be drinking) and the cost of the meal since your diet will result in a less expensive meal...you were okay with the cost of the meal at first. When did alcohol being automatically included with the meal enter the picture?
If everything in this package is the same, just different location and rooms, I would probably go. If everything changed and now your $60 isn't paying for what you bought, it's perfectly reasonable to cancel.
Add to this, the friend sounds like she's returning your $60, so it sounds like the whole package was cancelled. Again, I think it would be fine to cancel at this point since the arrangements are different than what you had originally planned and payed for.
I think you need to have a discussion with the host on the details.
If I bought a package that included A, B, C, and D, and found that now they're dropping B and I have to pay extra for C, that is not what I signed up for, I would like a refund, please.