Can someone enlighten me on the purpose of the wheatstone bridge in the OPs circuit?
It provides a DC bias voltage on the USB D+/D- lines for "supply identification" with certain devices, eg. Apple iPhone, to tell the device what the power supply current capacity is.
https://learn.adafruit.com/minty-boost/ichargingHere's a good explanation.
Look at the schematic not as a Wheatstone bridge, but two separate voltage dividers connected to 5V and Gnd and D+ and D-.
OP: What's your actual power supply input going to be?
You can use any 5V regulator, just take your 5V circuit (buck converter or whatever), and just add the same identifier resistors.
Personally, I would get rid of R4, do you really need it?
Arguably you probably don't really need C2, either.
R1 should be changed to 49.9k, because 49.7k is not a standard E-series value.
(Also, calling both resistors R1 = bad. Even though they have the same value they should have unique names.)
R3 should be changed to 75k (standard E-series, which 74.9k is not), and I would also change R2 to 75k to set the supply current identifier at 500mA.