About to dive in dc vw bus conversion (reality check)

After a few years with the idea brewing and the last ~5 months of researching I have found what seems to be the best deal and am about to start my first ev conversion. Before I pull the trigger I'm looking for a last minute reality check to confirm I haven't missed anything too significant.

Also keep in mind I'm going for bang for buck as well as reasonably plug and play - busy engineering student. And all quoted prices are in canadian dollars.

The van is a 78 hardtop so 2900lbs unladen and 5000 gross weight. ICE is about 400 lbs.

I have found a warp 9 motor with zilla 1k controller already in a completed 144v conversion from ~ 6 years ago. They drove it for 4 till the lead acid batteries died. Asking $1370 I will need to modify the coupler and adapter or source a new one.

I've also found leaf modules locally for $95 each but they only have 18. Which I believe puts the pack at 130v nominal and 50ah. I was planning on gettting started without a BMS.
I think this pack will hopefully give me around 15-20 miles.

Being a vw van I do use it for trips and to get to the surf from time to time so my plan is to use a range extending generator mounted either in the engine bay or on a small trailer. Generator would be between 5 and 15 kw. Because the van only got 20 mpg on a very good day and had next to zero emission control I think I have some wiggle room around the efficiency of the setup.

These sites were much of my inspiration for the range extender
https://sites.google.com/site/vehiculevert/
http://www.instructables.com/id/DIY-Plug-In-Hybrid-Car/

So a bunch of questions:
Does the setup seem capable of pushing the van around up to highway speeds (~55mph)?
Is the pack of a high enough voltage? (I was thinking of at least 144v)
Do leaf modules like to be kept together - if I decided I needed the extra power could I bring up the voltage with modules from other packs?
Will the charger from the 144v lead acid conversion work with a 130v lithium pack in a series hybrid configuration?

And any other comments/ advice is greatly appreciated!