HI, you can find a lot of info just searching on this forum.
I would start from these stickies:https://www.pizzamaking.com/forum/index.php?topic=14506.0https://www.pizzamaking.com/forum/index.php?topic=20479.0
The leoparding is not the only factor (and for some not a factor at all), for a good Neapolitan.
If my memory does not fail me, a wood-fired oven is part of the disciplinare (production standard), but you can achieve Neapolitan style also with a gas oven.
Requirements are the high temp 850+; a good flour that operates well at those temperatures (Caputo, or a also a mix), higher hydration (search for dough generator), an oven with a good heat balance (you want to avoid overcharred bottom for example) and if you want to be a purist a sourdough fermentation, preferably at room temperature (this last requirement is still a matter of debate).
I would also stress the importance of ingredients. Stay away from pre-grated mozzarella, buy real mozzarella. Also buffalo mozz is not a requirement and actually can make it too wet.
In sum, there is less emphasis lately on the requirement to use wood as fuel (speaking from my experience, I bought a residential Pizza Party that can be used both with gas and wood, and plan to compare the results soon). Anyway, when Sorbillo opened La Casa Della Pizza a few years ago, he only installed a gas oven. This would have been considered heresy until only a few years earlier: http://www.scattidigusto.it/2012/12/10/chiedersi-se-il-forno-a-gas-e-la-nuova-casa-della-pizza-napoletana
So if gas is your only option at the moment, go with it, so long as the other parameters are met.