it's not totally nessesary to paint rosewood. it's totally up to you, and your wallet!
do ya want an exact repro of harison guitar or a better modern version?
yes vintage fender is 7-1/4" radius, this is only available on total vintage necks. warmoth 10-16" compound = lower action and no buzz or fretting out with bends, and is cheaper. available on vintage modern and pro necks.
vintage modern neck has headstock adjustment for the truss rod, harisons tele likely had a heal adjusted rod. the total vintage is like.
i do not know if his had the skunk stripe or not, total vitage/vintage modern neck has the stripe, warmoth pro does not.
warmoth pro neck side adjuster for the trus rod, unfortunately for you, is not available for lefties. so unless your a real purist i'd sugest vintage modern. no need to remove the neck to adjust the truss rod, and slightly cheaper.
1-5/8" nut with is vintage fender, some like the 1-11/16" better.
stainless frets rock! the 6230 size, ss or nickel silver would be the vintage but the 6130, 6105 and ss6105 are popular on modern instraments.
and specify your tuners. that's about it for the neck
the body is easy. normal tele pickup route, vintage bridge route unless you want a modern brige for proper intoantion, top routed tele control route. and then 1 2 or 3 peice body, warning a one peice body will be quite expensive. this is not going to be a cheap guitar! not as pricey as a high end gibson or prs but not cheap. it's worth it though as warmoth quality is the best.
easy to assemble? well can you solder, can you setup your own trussrod? can you set the intonation and string height?
yes warmoth parts have a great fit and finnish and assembly is very easy, very little drilling, but a guitar is only as good as it's setup and a curcuit is only as good as the weakest solder joint.