I've done a strawberry ale a number of times that is a neighborhood favorite. I'm not big of secondaries so I add my strawberries after about 1-2 weeks, directly to the primary and then let them sit for about a week. By the end of that time, they look pretty rough, but once you pull them out, the flavor is great. Not that it matters with a stout, but my strawberry cream ale comes out clear, even without the secondary. So a couple of takeaways for what you're doing
- Don't add the cherries to your bourbon/oak. They'll get nasty after a week and you won't want to put them in your fermenter.
- Don't worry about a secondary. Soak your oak in your bourbon then pitch that and your cherries directly into your primary after a week or two of primary fermentation. Since you're doing a stout, no need to worry about clarity, which is the only reason to need a secondary to begin with.
Hope this helps!