Ideally; (if you don't have a sharpening stone, pick up a good flat stone you find and carry it with you.)
#1) One fixed chopper (5"+ all the way up to machete or axe):
-a chopping knife "can" still do smaller knife's tasks better then a small knife can chop, so for me it's #1, and if stuck in the wilderness for a length of time, while downed limbs and branches can be found, chopping can become a basic "need", clearing a trail while hiking your way out, or building a longer term shelter then just a lean-to, or processing wood to burn more efficiently, (and if you would have to defend yourself against a bear, a 3" knife just won't do very well

). I would prefer right around 6" give or take + and axe, or one good machete 14-18" that can double as both. If you have an axe it still behooves you to have a knife, (though you can get a thinner profiled blade as "heavy" chopping won't be necessary), if you have a heavy duty chopping knife, or even a machete, an axe isn't really needed. But I just prefer chopping with an axe over a machete, and a 6" blade can suffice for clearing brush while hiking. Extra weight, yes, so it comes down to what you can carry to suit your needs.
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#2) One fixed Carver/slicer around 3-4" - the larger blade "can" do finer tasks, but this just simplifies things for cutting up fish/small game, fuzz sticks, daily chores, whatever; and having two blades instead of one stretches the life of the edges on both, and/or God forbid one breaks or you drop it off a cliff... this where your Mora's and Neck knifes really shine. Shoot, bring two, keep one on the bottom of the pack "just in case": Not much extra weight, but an invaluable tool to have.
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One multiblade slip joint - not a need, just good to have. Takes up little space, use it for misc. tasks, or just to whittle wood to kill time while waiting for a rescue... I prefer congress styles and trappers, sak's, but stockman's, Barlows, whatever suits your fancy.
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#4) One solid locking folder (optional) - is the least important blade to survive with, because if the lock fails it becomes all but worthless unless you remove the blade to make a spear or small fixed shank, (or happen to have the tools and pieces to fix it), there is just too much that can go wrong, but, lets face it, we all love 'em, at least one, and we almost always have one on us, they're small and easy to carry with clips, so why not...