I voted for all five. Why? Because every Link can appear in Smash Bros. 4. How? I'll explain. Again. For about the fifth time on these forums.
There should be a general Adult Link character, and a Child Link character. They are interchangeable between OOT Link, TP Link, SS Link and Wii-U Link (read last paragraph) at the menu, and act like colour schemes of each other, only it changes there models, animations and voice, while keeping the same general moves and attacks. The same for MM Link and WW Link, which keep the same differences from Adult Link, such as running faster, jumping higher and being weaker.
The models of each Links swords, shields, bow, boomerang, bombs and clothing would come from each of their respective games. For example, OOT Link uses the boomerang from OOT and TP Link uses the Gale Boomerang.
Everybody would be pleased and be able to pick their favourite Link. It doesn't even fill up lots of spaces in the roster, which has been stated that it will not be much bigger than Brawls. Balance would not be an issue, because each Link would be almost identical, and there only differences are there physical models, voice and animations.
Also, remember when Smash Bros. Brawl was announced in 2006? Twilight Princess wasn't out yet, and yet featured Twilight Princess Link. This can be applied to Smash Bros. 4. It could, with a chance, feature Wii-U Link, even if it isn't released. Heck, SSB4 Link could even be based on the Wii-U Tech Demo. Ganondorf's Design in Melee was based on the Gamecube Tech Demo.