Hi
I didn't realise your kit was not a wrap around bridge and see it is a tunomatic style. I cannot really comment on the quality of the kit version, it maybe ok. The kit wraparound was way too high for a decent action but your maybe ok. Other builders may have an opinion. In terms of buying components checkout https://www.realparts.com.au/ They are australian based and offer free express shipping. Amazon US will take forever to arrive.

I am not sure about the Brass bridge, i reckon simpler is better for your first build. If budget is a concern I would recommend the Bone upgrade from Pitbull and put the money into Pickups. The Toneriders are excellent value for money and sound great. A luthier at my guitar school was pretty impressed with their tone. However pickups come down to personal preference.