A little confused here....you want to put together a five knife bush set? Or looking for individual recommendations on those?
First, go with the B.O.B. either way. Great knife, IMO.
I would replace the Tom Brown tracker with a quality Rigger's or Carpenter's hatchet. I think it likely you will find yourself staring at and fondling the Tracker a lot but also sitting in camp wondering what the hell you can come up with to use it for since you're fully covered for anything with four other diverse blades that will do it easier. It's also a boat anchor.
As for the TOPS, I like it. It's awfully close in size to the B.O.B. but might barely qualify as a different category of knife and keep your spread going. This would be the wild card spot though if you wanted to go slightly larger to give more spread from what the B.O.B. can do.
I'm a kukri fan. It certainly has a place in a bush set. Get a good one and a REAL one---don't get off into the fantasy profiles of kukri.
Only flaw I see in your setup is you have three blades pretty close to being the same thing. You could put more spread in there to handle a greater variety of potential bush tasks. I think
collim1 is right, you need to throw a heavy knife in there....something approaching BK-9-ish but no larger. I sure like the Cold Steel Trailmaster too.
Finally, let's face it: the TOPS and Ka-Bar are basically 'duplicates' in your structure. I'd replace one with a machete or bolo, depending on what you'll be hiking through. I prefer a bolo for most stuff.
If you've made a major error here it's not listing a good Vic Swiss Army Knife. I'd get one.