In the long run electrics will save your company money. Initial cost is a bit higher for electrics but in fuel, maintenance cost & longer economic life. The key to successful ownership is to make certain personnel are trained on proper charging & maintenance procedure and make certain they know when to use the charger EQUALIZE charge cycle. Have your selected lift truck rep bring in his battery "expert" to explain the ins & outs. Spend a few bucks for a single point battery watering system - preference is the one that has a visual indicator that lets you know each cell has been filled (a little white dot). Suggest you make one person responsible for all of this - otherwise it is "finger pointing time".
There are some tax benefits for converting to all electric in California - have your accounting guy check it out.
With low hour usage like you have you maybe able to qualify for a 72 or 84 month lease depending on the operating environment.

My personal advise is to stay away from CNG - reasons:
1. Lower engine power (about 20% less power than LPG) - some say a lift truck with CNG doesn't have enough power to pull a sick dog out of bed.
2. Requires an on site investment in a fill system (no tank exchange possible) plus the system is more expensive than LPG
3. Only one lift truck company offers a CARB approved CNG system - others discontinued the offer years ago.