A: Some families set up a limited liability company to manage family vacation homes. With the appropriate operating agreement that defines everyone's financial responsibilities, and which defines who is responsible for repairs, taxes, insurance, etc., it can work. But be clear, what you are proposing is a family /friend business. And the business is management of the real property. You must consider a worst case scenario where family and friends no longer get along. You must also consider what happens when one or more become ill and must liquidate their interest. There are so many possibilities. But it can be done.
A: This is such a common issue. When love fails, it often leaves a forced business partnership that must be terminated.
If you are on title, you are a co-owner. If you were unmarried, it is possible that the deed designates what percentage of ownership you were granted, if not 50%.
The co-owners can make claims against each other for reimbursement of costs that should be shared. And that can be a messy process (who paid the insurance, who paid the mortgage, who paid for repairs, etc.)
If a split can't be negotiated, there is a court action called "partition" that forces the sale of the property, and where the expense claims can be litigated.
A: Not to be too glib, but you should add all the laws and legal requirements for your particular type of transaction, and the requirements you seek to enforce or avoid. It has taken me 32 years to do it correctly. You should consider finding someone in you County with similar qualifications.