I want to use E10 socket LED bulbs in my streetlight models so I can just connect the wires to the terminals and no soldering. For now I just want to use a waterproof battery box with AA or C or D batteries or possibly 9 V. The lights will be wired in series. Can someone suggest to me what voltage of bulbs I should use and what kind of battery. I want to get this project going but I don't know what I need to order. I see all kind of bulb voltages on eBay and not sure which are bright enough or if I need 1.5 V or 9 V batteries. I have some CdS cells also so I may wire one into the circuit.

The retrofits are designed to operate on certain constant voltage source, so contain some ballast inside.
The problem is, you will never know, what ballast is there and what rating reserve it has. The only thing that is sure is, they are designed for a constant voltage operation.
Therefore connecting them in series may form an unstable setup, or at least very poor voltage balancing among the ballasts, both resulting some operating at lower voltage and some experiencing higher than designed input voltage, so may die very soon.
The most problematic are SMPS's (only the higher power variants; inherently draws less current at higher voltage, what makes the series chain really unstable) and then those with thermal foldback (most linear constant current regulators, so the better quality models; the thermal feedback in the ballast chip makes the current drop at higher voltages, so the same instability when operated in series).
The only safe are the ones using just a plain resistor, but this is present only in the cheapest models and even with that you could not be sure (the CC thermal foldback regulators aredirt cheap and because of the foldback suffice with way simpler thermal management - therefore popular among cheap makers).

So better connect them in parallel.

For the voltage, it depends on what you find in the colors you need...

I'd recommend D cell batteries..