Of course there is no written contract between the band members. There almost never is.
And there is almost always problems that arise after members leave a group. Who owns rights to which sang, who owns the rights to the band name, logo, etc. It can become quite difficult. (It is interesting that a band can sign a contract for a upcoming gig, but never sign a contract between themselves.)
Your situation is wrought with perils which can not be answered in a simple forum such as this. You need to discuss with an attorney, in confidence and in detail.
In an ideal world, each band member would come to a mutually agreeable resolution concerning the ongoing band as a business and any departing members interests fairly resolved. This would (again, "ideally") result in a written agreement where a fair and equitable distribution of intellectual property rights is insured for everyone. Copyrights may be joint authors or single authors, trademarks may be joint or singly held, and those rights need to be clearly defined and everyone needs to agree on how to manage those rights.
Feel free to contact me or any of the excellent attorney's here on AVVO as most of us offer a free initial consultation. Unfortunately, I can not be much help as you need an attorney licensed in Florida. Your best bet is to find an attorney near by who can meet with you and eventually meet with all the band members to explain the resulting proposed resolution.
I hope you have success finding replacements prior to the upcoming gigs. Good luck.
My disclaimer is simply that Avvo already has an adequate disclaimer.
You need to consult with an entertainment attorney as soon as possible to avoid any legal issues later. Search Avvo.com for an entertainment attorney in Florida.
Ivan J. Parron, Esq.
With or without a contract, band members who have created problems will more than likely continue to create problems in the process of parting ways. There are many issues that only an attorney who practices in Entertainment Law can accurately answer for you. Use Avvo's Find a Lawyer tool to find an Entertainment attorney in the Orlando area. If you are interested in using an Entertainment attorney outside of the Orlando area and don't mind communicating primarily through phone, e-mail, etc... Charlotte Towne in Fort Lauderdale, Florida is a great choice. www.charlottetownelaw.com/ - (954) 306-6624.
Best of luck to you.
Ian M. Thomas, Esq. - Tripp Law Firm, P.A. - www.trippfirm.com The above answer should not be construed to constitute legal advice and does not create an attorney-client relationship. This information is intended as educational only and you should seek a qualified and experienced lawyer with questions about your legal rights. The hiring of a lawyer is an important decision that should not be based solely upon advertisements. Before you decide, ask for free written information about the lawyer's or law firm's qualifications and experience.