I don't know about the longer lenses but the carl zeiss jena 25mm is a classic.
The jupiter 6-2 180mm f2.8 is a copy of the 180mm carl zeiss jena f2.8 lens. This one is quite rare. If the copy is anything like the original it should be stellar.
The MTO-1000a is also quite rare and should be worth a penny or two.
I would just shoot with the kit, but get another body, like a spotmatic. The Zenit ttl has the worst viewfinder of all the zenits I've tried.
Kind Regards
Mads