is it that you particularly want to make a dress? if not, then i'd seriously consider ordering the dress on your first link!
but in answer to your questions
link 1: possibly link 2: definitely won't work in lycra (too many panels) link 3: best one so far but you'll have to tweak the pattern a bit (otherwise it'll be too big) link 4: are you planning on making it as a top and skirt or as a dress? the top for this is already in a stretch so it would be possible to extend it and make it into a dress.
are you able to buy some cheap lyrcra? if you are then I'd go for link 3 and try it
I've had a go at making dance dresses for Latin and freestyle ( basic outfits) and have used American/ Canadian ice skate/ dance outfit patterns with longer skirts. Try having a look at the Kwik sew web site (patterns available in uk via a company called habithat) and Jalie ( which come up small so do a size bigger) also there is an American seller on eBay who sells 2 panelled dance dress patterns (search latin/ ballroom patterns). Also look on eBay as discontinued patterns come up again mainly US and Canada, but you get some in Australia. Obv you have to take shipping into account. I was also recommended a book called (i think) Sewing sport and action wear by Kirsten martensen which I found great when I started totally from scratch. Also have a look on The Sewing Forum as it had a sub board on dance although it's mainly ballet tutus you can pick up info on patterns and fabric / trimming suppliers.
I've read the rest of the thread, I've spent ages on google researching pattern conversion to Lycra fabrics. I was told to look for pattern for stretch knit fabrics and go down one or 2 sizes depending on how snig a fit was required, as unless you buy a leotard pattern there will be no allowance for the stretch and fit. I think it's harder for patterns that are designed for non stretch fabrics. Take a look at this site http://www.lagassa.com/gowns/stepbystep.html Also search this eBay item no 300348330961, they also do a halter dress pattern.
i'd say steer clear of lycra and make the dress you just linked to out of satin. this means you will only have to alter the pattern to fit your dd instead of pretty much redrafting the whole pattern for lycra.
i really don't think organza would work for the godets, it would be too stiff. chiffon would be better