I've owned 7 Samurai's and out of the ones your looking at, I'd go with the white tin top. I wouldn't touch the first one with the high miles and mods.
Like someone else said, don't expect great fuel mileage out of Samurai's. The best I've ever seen out of any of mine (not counting the diesel one) was 25 mpg. Most of the time they got 20 mpg.
One of mine was a 94 with the EFI and 16k origional miles. The do have a tiny bit more power than the carbed version but I wouldn't let that stop me from buying a nice older carbed model.
As far as VW diesels in the US, we also got the 1.6 turbo diesel. The 1.9TD can be had easily here in the US even though we didn't get them in any cars. I bought my 1.9TD as a complete crate engine from the local VW dealer. I see them on eBay all the time as well.
Even at 25 mpg though, that's considerably better than my truck I currently use for my DD. Plus, it gives me a spare vehicle, and one that is no longer depreciating much (in dollars, not percentage), so it doesn't hurt to pile up miles.
Long run plan will be a tdi swap. Once I get one I'll keep my eyes open for a good deal. Are the 1.9's (us version) really that much more difficult than a 1.6?