There's a thread going on about the merits of 35" scale basses. I love the B's on both my 34" Sadowsky and Alleva. Both of these basses are designed (similar to the Lakland) with VERY stiff necks. I wouldn't really worry about the scale length.
However, obviously, a vintage oriented, single coil bass is going to sound very different from the modern, humbucker 55-94, so in that way, the B will differer... from very large and big on the 55-94 (IME) to more of an extension of the E string, which I prefer.
Regarding the P/J, I wouldn't think that would be a big problem, but Jimmy would obviously be the source for that.