Teleconverter on Nex kit zoom lens?

The 58mm thread is the requirement (as long as it's a bit larger than the lens you're adding it to).  Many Olympus Tcons are smaller or may use a bayonet (I think).  I'd consider the Oly adapter superior, with a Tcon 1.4 probably a bit better - sharper results - than the Tcon 1.7.  Like everything, it's a trade off.  If you always use a tripod or steady rest and an optimal f-stop and shutter speed the 1.7 should be pretty good.  Remember that the Tcon is a big heavy chunk of glass and metal hanging off your little Sony lens, so be kind to your lens.