The SMX will lee is a 22 fret version of the standard J/J. No will lee pre, no VTC, and all SMX’s come with standard single coil pups already, so that too will be akin to a WL. You cannot add a VTC to the current line of SMX basses. (The current SMX pre can’t be modded) You’ll need to purchase an entire new plate/assembly. If you really wanna emulate a Will Lee’s electrics, you can purchase a Will Lee pre and install that. That, with the 22 fret neck will give you a closer experience to a Metroline, but with an Okoume body and a roasted neck vs the Ash bodies your using now.
Regarding your question about the fretwork and weight of an SMX bass vs your current japan made models: . The SMX line now has the semihemispherical fret ends vs standard beveled fret ends like on your Japan models. The difference in feel is negligible. The weight of most of my Japan basses came in around 8.5- 9lbs for a 4 string, just over 9lbs for a 5. The SMX’s that I’ve worked on can be as low as 7lbs 14oz or up to 8 3/4 on 4 strings,to just over 9lbs for a fiver.
If you’ve become accustomed to Japan models, and you have the additional budget, you may want to consider a Japan unit. it’ll require no mods, and the build quality will be top notch, IMHO.