Regarding a Florida holiday rental (4bed, private pool).
Could I deduct the cost of attraction tickets, such as theme park tickets, shows, events and such like if I use this first hand knowledge to advise my guests via Sending email files (“things to do”) or highlighting attractions in my marketing (including website)?
I'm assuming you are talking about tickets to attractions that you buy for yourself or your family. No you cannot deduct them even if you are "advising" on local guest attractions. These are personal expenses.
They may be deductible if you're buying them for your renters, but then we enter the "ordinary and necessary" conversation...