So . . . do they work together?
EWP rather thoroughly "affect(s) the use of a particular type of weapon".
And even going with the unofficial errata, it does say "choose a weapon".
So would you be able to use any exotic weapon with the aptitude weapon enhancement with just one EWP feat?
It really seems that way by RAW, even the RAW of the optimizing players who tried to fix the ToB.
And, since you are no doubt wondering where this is going . . .
"Everyone" knows about the Morphing weapon enhancement, which lets you change the kind of weapon within a particular type - Light, One Handed, or Two Handed.
While contemplating how to abuse that, I thought of the Changeling enhancement. Though it can only be added to a spear, it allows changing between a shortspear and a longspear, so now you can any One Handed or Two Handed weapon.
Naturally, I was still not satisfied with that, so I kept looking. There had to be a way to get Light Weapons in there!
And it is worse than that.
The Everchanging Blade from the FR Underdark book. Whose text reads:
"This +1 metalline morphing sizing longsword can become any single +1 weapon the wielder desires."
Yes, I know a morphing weapon cannot do that.
Yes, I know a sizing weapon cannot do that.
Yes, I know metalline has nothing to do with this, and even if it did a metalline weapon cannot do that.
Yes, I know the price is 50,315 gp, or a standard +5 weapon. which is what it is. (+1, metalline +1, morphing +2, sizing +1)
It can change into anything you desire.
Not merely changing from Light to One Handed to Two Handed.
It can become a missile weapon - long sword to long bow!
Sure, the metalline does not help, but who cares! Your sword is now a bow.
Once again, the RAW is right there, with no errata.
But wait, there's more!
Never mind your long sword is now a long bow like the silly Elven weapon, your spiked chain is now a composite greatbow.
Add Aptitude to that sucker and as long as you have any EWP you are proficient, and a bunch of other feats apply just for the fun of it.
As for convincing a DM you can make an "Everchanging Shuriken" at 1/50th the cost - or 50 at full cost, then share them out among the party so everyone has whatever weapon of whatever size they want at all times, I disavow any knowledge of your action.