I actually watched the video. Here are a few things you should add…
I think your wasting resources which custom trades of fossils. Your better off trading legendary creatures.
I would agree with you about keeping your market clean, I would differ with you about eliminating all the legendary creatures from it. Yes, you get fossils essentially for free (coins are worthless). But when you get a trade harbor offer for those legendarys, the value far exceeds the offer for the fossil. In custom trades legendarys fetch 600-1000 LP. I would say the best custom trade would always be legendary for LP.
In regular trade harbor, the trades for legendarys also exceeds return on fossil. Again, I know you get the fossils for free. But you also get the legendarys for free in pvp battles. I probably have 400 legendarys in my inventory that would exceed the return of the fossil. All earned in daily challenges and pvp battles.
So while i would agree with you keep the harbor empty of all but fossil, I would say keep you legendarys in there that you never plan to hatch. I will post pics as those offer come in.
Also another way to get around your lack of fossils in Your market is use a few a few as park multipliers. That way if you get stuck where you desperately need 2 and market is down to 1, you can pickup one or two that are already being used in your park. Replace them when crisis is over.