How difficult is it to get permission to use icons from a popular, classic* show in a tribute episode? Is it just mechanical* fees , or do you have to negotiate with the IP owners?
As an example, the Mythbusters made an episode all about the A-team. They used the shows theme tune, made a van to look just like one in the series, and even had Adam dress up like, and use the mannerisms of one of the characters.
Obviously, getting approval from the original creators/staff is much preferred, (especially if they can provide additional support like design documents, advice, insights, and the like), but is it really necessary?
*by mechanical, I mean similar to the system used for songwriters, where you just pay a set fee to a coordinating agency.
IP laws leave a lot of wiggle room for lawyers to argue over.
Mythbusters sometimes aired clips from a movie/TV show that contained the myth they were investigating, but a lot of time they didn’t. This had a lot to do with how easy/cheap it was to get rights to the clips. (In fact, like the Green Hornet episode it was clear that the studio paid for the show to promote the movie.) I don’t think they ever showed a clip from a Jame Bond movie despite having segments concerning those movies many times. Hence a lot of clips from old silent movies. (Even if not in the public domain, the owners of the clip libraries don’t charge much.)
You can generally do something like dress up like an A-Team character and do some jokes about them and the show. Parodies like this (but not all “parodies” are parodies) are okay since it’s considered unlikely to cause confusion with the original.
Some studios are pickier than others about using trademarked figures and such. E.g., having a bunch of people dressed like Star Wars Imperial stormtroopers is not going to get you sued unless you start making a commercial-grade Star Wars fan movie.
Secondary items, like vans and such are sometimes trademarked and well protected but generally aren’t.
“Mechanical” doesn’t mean default fees for music. You might be thinking of “compulsory mechanical royalties” or some such. (The keyword is “compulsory”.)
For music used in a TV, you definitely want to negotiate a lower fee. For non-music, it will be negotiated no matter what. There is no universal standard for how much to pay for using a 15 second clip of something. One major factor is how many people are expected to see it. A rinky-dink local show won’t be expected to pay as much as a high-rated national show.
The difficulty usually comes down to price but there are some IP owners that just say “no”. YMMV