If this is your first build focus on just the motor bits first. let the looks come last. only thing worse than a non running bike giving you the run around is a pretty, non running bike giving you the run around. so kit it, tune it and make it rip, THEN tear it apart and do the custom stuff.
personal thought on your parts list:
kit, good stuff make sure you chamfer the ports. and match your transfer ports in the case to the new ports on the kit and match the exhaust to the new pipe.
gaskets, of course get those, crank bearings are 6203 if memory serves me correct.
15 SHA. its an okay carb. its easy to tune, BUT you have to kinda tune for top end and have your mids and low revs be kinda rich. You also will need jets to tune the carb as well. you can use this spread sheet to see what other people using simmilar set ups are using for jetting and speeds they are getting.
ALSO NOTE: if you run a 15mm carb with your stock 12mm intake, its basically the same as running the 12 carb. the flow can only be as good as your restrictions. so get the appropriate intake and also get some new reeds, you'll thank yourself.
short cone filter, honestly don't waste your money on a filter. if you're paranoid put some pantyhose over the open carb with a hose clamp. this is a personal opinion. if you really want it get it.
pipes a good choice. I like the regular one a lot, and honestly the pipe on it would do fine with a 70 kit. its not a super top end ripper but it will get you going.
27 tooth. solid move. maybe mess with the rear too but don't go crazy. make sure you get the right front one though. you might need a dished front. if you order a flat the chain alignment will be off and vice versa.
low bars. you do you boo boo. but they will make ya back hurt.
80mph speedo. haha keep dreaming ;^) speedos on mopeds are silly to me.
if this is your first build I would HIGHLY suggest instead getting a head temp sensor to help with tuning.
speedo holder, see comment above.
round headlight. whatever go for it m8.
the rest of it is pretty much whatever ya want stuff. i think the paint looks plenty good. nice blue. get a good 415 chain, and a good throttle. With throttles i like to go with mid range the super cheap ones tend to be brittle.
THINGS ID GET:
blue first gear clutch spring.
Yellow second gear spring
Seal nut for sprocket.
lil note on the seal nut, Tomos motors have a self lubricating chain (seal behind the sprocket goes out OFTEN". they like to fling oil all over the rear of the bike. so don't paint it white haha. the seal nut helps this not happen..... as much.
good luck and have fun. take your time. don't loose shims, yadda yadda.
OH and if you have not built a motor before don't start until you have everything. leaving a motor open and apart for days or weeks only helps you forget how shit went together,