Sage Advice from Sour Brewer Sought

Ok, so here’s the back story. Six months ago I brewed up a Flanders Red, it was my first ever sour, it used Roeselare Wyeast and nothing else and has since been sitting on the yeast cake. I decided that I wanted to try making a sour beer every six months or so and have decided on a Oud Bruin as my next go mostly because I still have this giant yeastcake sitting around that could be used for it.

So, my tentative plan is to rack the Flanders Red and pitch the Oud Bruin on the yeastcake but I’m wondering if there will be any actual brewers yeast left viable in there after six months and if that actually matters. I know the other stuff is still alive and kicking but should I toss in some US-05 or something like that to help ferment at first? I think I read somewhere that someone did that. Or fermenting the beer first off on a neutral strain and then pitching it on the yeastcake?

Any advice would be beneficial on what has worked in the past or what is standard protocol.

I would ferment the Oud and then transfer to secondary and siphon up a little of the cake off the bottom of the Flanders, pitch that to the Oud.