Understanding VESC Hardware and $40 VESC target

Please let me know if this information exists elsewhere, thanks!

Target Motor: Pump; 3000-6000 RPM@70V,10A max - to run directly off Solar panels

I am aiming for a BOM cost of $40 for the VESC, and have selected the following components for a 100V-20A build

MCU: $3.5

CS Amp AD84XX: $3x3 = $9 (can there be a cheaper alternate ?)

Gate drivers: IR2113S = $1x3 = $3 (can we use these in place of DRV series?)

MOSFET: IRFb4115 = $1.5x6 =$9

Isolated Power supply: upto 200V in 12V out: $1.5

LDO, caps etc = $9

Board= $3

Basic TO220 heatsink $1

Total: $35.5

Rest of the budget: shipping,taxes,misc,etc

Questions:

- Does the above look ok ?

- Is there a cheaper alternate to AD84xx series ?

if this looks good, i'll start building one.

My commitment: if this works and if people are interested, will make 100 units available here @ cost+shipping as a thank you :)

FETs can always be swapped out for better performing ones.

My experience level: Done about 12 BLDC sensored and sensorless controller designs over the past 2 years - all trapezoidal control, never done FOC