Absolutely. If necessary try to negotiate with the tenant. If you have a buyer that wants to take occupancy prior to the expiration of the tenant's lease then offer to pay the moving expenses and downpayment for the tenants' new rental. Talk to your tenant and if necessary ask the buyer to make these concessions so that you do not have to lose money on your investment when selling.
Yes absolutely. Florida Landlord Tenant Law requires your landlord only to give you about 12 hours notice for showings.
The rental agreement will survive the sale so if the new owner wants to occupy as his primary residence he (or you) may have to offer a financial incentive to the tenant to encourage him to cancel his lease. If the tenant doesn't want to cancel their lease then you may only be able to sell to an investor. The Seller would have to transfer any deposits held to the new owner.
There may be other legal ramifications so you may want to seek the advice of an attorney.