If a pretty reputable hatchery sells it then I'm sure it's fine. I get my red lights from Tractor Supply. They're not splatter proof, but I don't have ducks so it's not a concern for me.
I don't think it matters what generation of EE an EE is since they are ultimately a mixed breed bird and only takes one generation of mixed breeding to make an EE. As far as them be recognized as Ameraucana or EE....there is a standard of perfection (SOP) with the American Poultry Association...
Really depends on the age. White Leghorns can lay as early as 4 months old. EEs are slower to develop and can take 6 or more months to start laying. White is not very likely for an EE to lay, so I'd say it's the Leghorn.
I got lots of help from this thread when I had a cross-beaked chick. https://www.backyardchickens.com/t/628361/diary-of-a-crossbeak-support-for-special-needs-chickens-and-their-keepers
I hope this helps! I've never had to deal with either of these, but these articles were very informative. Prolapsed vent- http://www.the-chicken-chick.com/2012/04/prolapse-vent-causes-treatment-graphic.html
Egg binding-...
I don't even bother trying to sex them until their feathers start coming in. Watch the comb and hackle feathers. I kept thinking this one was going to be a roo because of the color. Nope.