Yeah yeast and bacteria at the same time in primary is a good thing -- this is what the Wyeast Lambic and the Wyeast Roselare blends are. However don't feel obligated to make a lambic or a flemish red with either one of those though. You can make a nice malty brown ale with a rustic tart note in less than 6 months with Roselare. I've tasted Belgian Stouts primaried with roselare too.
I think you should experiment with both glass and plastic and see what works for you. There are a ridiculous amount of variables in wild brewing, and we as homebrewers cannot even begin to wraps our heads around all of it. We think we have a handle on it but the guys at Drie Fonteinen and Cantillon just roll their eyes...
Even after you've determined the bugs, the fermentation vessel, the recipe, temperature, etc you'll always have another issue to deal with. The key is to just start experimenting as soon as possible, with several batches, and start tasting them after 6 months. You'll be amazed at how much difference one month will make. You'll without a doubt reach your stride and stick to it after a year or two. Make several different batches and mix up different methods on each one, take lots of notes, and make IPA while you're waiting!