Tess. Morays and Greens will not work in that setup. Greens will max out at 8' - 10' and Tess. will eat anything in the tank, including other eels (your Zebra idea), as well as maxing out around 8'.
If you want other semi-aggressive suggestions, that'll hold their own against that stock list, look into Whitemouth Morays or Hawaiian Dragons (I own both).
Clown and Queen Triggers will not work that list...not just with the Lions. 300gal, unfortunately, is not big enough to control their territorial and aggression problems.
Unicorn Tangs will be too big, even for a 300gal tank, as they max out at over 24" and require an enormous swimming area.
As someone else said...you're going to need ALOT of rock work if you plan to house Morays, but you're going to need next to no rockwork if you plan to house sharks or rays. Also, to disagres with what jr2857 said...your tank will not be big enough for 2 Bamboos and you'd be pushing it with one, with the rest of your stocking ideas.
Two Volitan Lions would be alright (I own one that is 15" long). There may be some aggression, that will lead to fighting, if you're not careful though.
The puffer idea, however, would not work. They're very inquisitive and will nip, pick on and bite any bottom dwelling, slow moving fish (sharks, rays and eels).
My stock list, with what you want, would consist of the following:
2 Volitan Lions
male/female pair of Blue Throat Triggers
Either Whitemouth or DME
Blueline or Bluespot Grouper
What type of filtration are you planning for this tank?
