Personally … I wouldn't bother considering the baritone ukulele as a "baby" guitar … there's far more (or less) to it than that.
If you want to play a guitar, buy a guitar, six strings and all, and learn "full" chord shapes from the start.
You've got tuning variations enough on a five-string banjo not to worry about tuning any other instrument tuned in a similar manner … I use CGBD, DGBD and CGCD for claw-hammer on a regular basis, and there's always pegging the drone up a tone or two for a different sound.
My baritone ukulele is tuned GDAE, an octave down from a fiddle or mandolin, just like a tenor banjo, and serves well for practice of an evening or other occasions when a full-on banjo might be "socially unacceptable"

I think you'll find playing a baritone ukulele as a 5-string banjo will stunt your "real" 5-string banjo progress. A characteristic of the 5-string banjo is the long neck, causing some finger placements to be a little "awkward", without practice. Also, of course, the main characteristic of claw-hammer playing on the banjo is the high drone … something that would be totally missing on a conventionally tuned baritone ukulele!
You could end up being satisfied you've achieved something, having practised on the ukulele, only to find, when you pick up the banjo, it's not quite so easy

If you want something "different" as a cross-over between guitar and ukulele, try one of the small-bodied "travel" guitars.
My Washburn "Rover" has a body similar in size to my baritone ukulele, but with a full-size neck like my Epiphone Wildkat, (that's another story!), but tuned in "Nashville" style, effectively using half a set of strings from a 12-string guitar. The chord shapes are all standard guitar shapes but the sound is really quite different

As always … YMMV … good luck
