The voyeurism statute would not seem to be applicable, since the various clauses involve something sexual or exposing sex organs. Florida is a two-party consent state, meaning that you can't record oral communication without consent of the parties to the communication (Chapter 934). If the neighbor doesn't communicate orally, you might think that the recording is allowed. And it might be, but the statute circularly says
“Oral communication” means any oral communication uttered by a person
exhibiting an expectation that such communication is not subject to
interception under circumstances justifying such expectation
Since it is not self-evident that there is no expectation of privacy in your yard, and it is not self-evident that videotaping is not "intercepting oral communication" (yes, there were a lot of nots in that), abundance of caution would dictate that it is not safe to take such videos. A plain-language analysis of "oral communication" would indicate that taping a person's action of spreading trash doesn't constitute communication, but laws aren't always interpreted according to literal meaning of words. Recording the verbal harassment would, needless to say, be illegal without consent of the neighbor, since verbal harassment is oral communication.
Under Florida statute 934, recording an oral communication is subject to what is widely misnamed the "wiretapping" law. "Oral communication" is simply defined as an oral communication, with the additional proviso regarding expectations of interception. "Interception" includes as "acquisition of the contents of any ...oral communication through the use of any ...device". There are exceptions such as "using a hearing aid", which are not applicable.
934.03 (1)(a) identifies the act of "Intentionally intercept[ing]...any ...oral...communication", as well as (c) "intentionally disclos[ing]; and it says that a person who does this shall be punished. There are then "notwithstanding" clauses such as "authorized by law to intercept". 934.03 (3)(d) states the applicable two-party consent requirement that
It is lawful under this section and ss. 934.04-934.09 for a person to
intercept a wire, oral, or electronic communication when all of the
parties to the communication have given prior consent to such
(emphasis added). In the applicable context, the neighbor verbally harrassing the friend would constitute an oral communication between the neighbor and the friend. We may assume that the friend consents to the interception sine he is making the recording; in Florida, though, consent from the neighbor is also required.
While it may be the case that the original legislative intend behind such law was to prohibit law enforcement from literal wire-tapping, the wording of the statute is broader. The law applies to "any person who", not just law enforcement. There is no clause that says that "this law only applies to law enforcement". Since the neighbor is on his property, that passes one of the fundamental tests of expectations of privacy. We have no evidence that the neighbor was acting in a publicly-demonstrative way in a fashion indicating that he was communicating the harassment to the world at large. though that would be the obvious tack for the friend to take to defend himself against charges of violating tat law.