Willpower and Presence get picked to balance out, but note that Presence should be close to Per, and Willpower close to Strength for mechanical conversion. (That is, a character with high strength should have a high WP in Edge if you want him to soak damage the same way he used to.)
Don't forget that the Willpower skill in D6 is actually a Knowledge skill. So I'd probably have the middle of Strength and Knowledge be Willpower, or wing it depending on what or who is converted.
General enemy stats wouldn't be much of a problem, though, seeing as most common foes are statted in Edge. Converting major NPC stats is something else, of course.
Equipment is left rather vague in Edge, but prices from D6 should be about the same. And equipment should basically do whatever it says it does. In game terms usually eliminating setback dice or adding a boost die. Most basic equipment is covered.
Vehicles is another story, obviously. But for most basic examples, and a few iconic ones, you're covered unless you want to do the extra work.
Something else that's nifty about converting between D6 and Edge would be the challenge system. If there's a noted difficulty for a test in a D6 adventure, it's easy to convert the D6 difficulty table into Edge. I don't remember how far the D6 one goes, though, but I imagine it's a little longer than Edge's because you could get quite high check results with a seaoned character in D6, so it might need some shortening.
Then of course, the fluff is still there. As an example: Our group has a player who's escaped from Tapani, but we plan on eventually return there. The GM is utilizing his D6 stuff on the sector.