Loss of lower leaves is normal - as plants grow new leaves, they get rid of the old ones. It's not a lack of minerals so much as a natural fact.

As to your etiolation problem, you've probably guessed that you need to increase your light levels. Do a search on this forum for supplemental lighting (I'd tell you, but I can't tell you much as I don't use them).

Lastly, most Crassulaceae (the family your Echeverias are in) are opportunistic growers - if it's warm, lit and there's some water they're going to grow, so I'd be careful about classifying your Echs as summer growers.

Hey!

There is a thread on here where we talked a bit about grow lights. Here is a link...

http://forums.gardenweb.com/forums/load/cacti/msg0313154121061.html

Hope this helps! I think the main take home is to make sure the light is as close to your plant as possible. I am still working on that myself. Good luck!