The agenda item is not correctly worded. The agenda item must give the council the choice of whether or not to exclude the public and press, so it should read something along the lines of "to consider a motion to exclude..." A simple majority (chair's casting vote if necessary) will decide whether or not to exclude, so you do have the right to determine that the item be discussed in open forum.
If the chair has written advice from the County Council, that should be presented to the meeting as part of your deliberations. If it isn't written advice, in context, I'd be tempted to ignore it. From the information you have provided, it seems highly unlikely that the County Council would have issued such advice, unless the potential litigation relates to the length of the grass at the funeral. A County Council cannot issue advice that contravenes an Act of Parliament, so legislation always trumps individual opinion.
Looking at all of the connections you've highlighted, anybody who has a connection with the PCC should declare a non-pecuniary interest and their involvement should follow the rules set out in your code of conduct. In a controversial situation like this, the council must take extra care to follow its own policies and procedures.
Finally, the request from the complainant to withhold funding must be ignored. It is vindictive and may subsequently be used as evidence in legal proceedings to suggest that the council believes that the PCC is at fault.