I don't know why a solo trip wouldn't be fun. The people are friendly and will make you feel right at home. Didn't find any unfriendly tourists either. There is just something about that little island that makes everyone grin from ear to ear.
For snorkel/diving look up Tulu. He's a ton of fun. A search of the archives will find you his phone numbers or just ask anyone after you get there. He is well known. No info on other tour guides; he's the only one we used.
Can't help with the hotel question but am sure someone else will.
Money on food and drink is going to depend on where you eat & how much you drink.
Seems drinks averaged about $10BZ [we mixed our own most of the time] Food was anywhere from $5BZ at the park vendors to $35BZ for the bbq's and the eveing meal at Elvi's. It will get higher at the more upscale restaurants.
Your gain is your friends loss. They don't know what they will be missing.
The best tip I have is to pack the watch away while waiting for the hopper, put on a big grin, have a rum punch, get on island time and soon as your feet hit AC kick off the shoes. And pack half of what you think you'll need!