Which bike to build? Help!

First off, welcome to the forum.

This question keeps getting asked over and over again. Your build totally depends on you... we are not there and we will not be riding the bike ever. Figure out what is your style and go with the one that feels and looks the best to you. If its your first build then I'd say go with the single speed, less things to worry about maintaining. Which ever one has better brakes

Do a search and see what other members have done with those bikes.

That's an easy choice in my opinion.
I'd without a doubt do the Jaguar.

Multi-speed rear hub so that down the road when you get sick of peddling out of red lights and stop signs you can easily put an SBP shift kit on and stop working that poor little engine to death running full throttle to get to 30mph.

You'll also have less trouble installing the rear sprocket rag joint on the multi-speed rear hub, the brake arm and dust cover on the coaster hub will need immediate attention to mount the sprocket.

Better brakes. You're right the coaster brakes ain't gonna cut it. You'll need to supplement those coasters with hand brakes anyway. Jaguars V-brakes will work very well right off the bat.
You'll be stuck mounting caliper brakes on the single speed, as the bike doesn't have cantilever brake studs welded on the forks or rear seat stays.

I just love the Jags looks aside from any and everything else, but that's just my opinion and you know what they say about opinions.
TiM

Dude I just built my first cruiser like a week ago and it is one of the best things I ever did. One thing I know you want to be sure on is how the motor is gonna fit. I boughta Electra cruiser which looks awesome and its a 26 inch frame but the bottome bar extends out which made mounting the motor challenging. Main thing is pick something cool. I was wondering if people would be making fun of me for making a bike look like a motorcycle but I gotta tell you my bike looks awesome and every where I ride people have questions. It may take a little to get it all together but once its done its gonna be worth it. Dont let other people ride it. They wont treat it as you would cuz they didnt build it. I let 2 co workers try it in the parking lot at work. They didnt do any real damage but once you build this thing you dont want scratches.