Welcome, A-Train!
We have a serious soft spot for the grossly naive here, so no worries.
bound to be reputible
Oh, my, these are dangerous words when relating to China or the EFL industry overall...
Don't assume anything or anyone here to be reputable! Your best bet is to ask around...which is part of why we're here.
For certifications, don't bother with online programs or others that don't come with face time. But a better approach might be...do you really need to bother with a TEFL certification at all? My immediate impression here is that you DO NOT.
Most schools in China don't require such a cert, nor does a cert typically bring one higher pay. You're well-educated and you already have classroom teaching experience...I recommend that you skip getting a cert altogether. You just don't need it.
It's good to go in with some ideas about where you want to live and teach, but it's also good to keep an open mind. A lot of nice cities in China aren't exactly household names in other countries. However, definitely DO thoroughly research any cities you may be considering, including asking us on here. A lot of Chinese towns have impressive websites that don't show you the unregulated smoke-belching cadmium smelting works that makes up most of downtown...
For finding jobs...I recommend avoiding the big international job-listing sites such as Dave's ESL Cafe, and focusing more on local/regional websites. The jobs listed there are often of higher quality! You'll find links to job-bearing websites in several areas of our Links pages; it'll be a great place to start.
You don't really need to speak Chinese to come here and teach. Things like counting and social courtesies are always nice, but your classes will either contain students with enough English to follow you or will have an assistant that will translate for you as needed. And trying to get around and get things done with little or no command of the language is much of the fun and adventure of being here!
Don't sweat this...if you have the time and inclination to take a basic Mandarin class before coming, it certainly won't hurt...but don't let a lack of language skills slow you down. Believe me- you'll learn some necessities very quickly, and you'll find plenty of opportunities to acquire the language while you're here. Chinese is one of the harder tongues to acquire as a foreign language, and it takes quite a long time to really get to a significant fluency in it.
Welcome, A-Train. You're in for quite an adventure, and we are here to help you.