Is it possible to make low-alcohol Limoncello?
There are plenty of recipes for limoncello/lemoncello out there that use vodka. I would reference one specifically calling for vodka rather than adapting one that relies on either 150 or 190 proof Everclear. 

The higher alcohol content means a stronger extract from the lemons (does not necessarily apply to leeching of sugars, just oils), and a corresponding need to be sugared down more. As vodka is easier to just sip and lower in alcohol, it would likely require less simple syrup, and either more lemons, agitation, longer steeping or a combination thereof.