UA/ANA is offering a very good price on a flight from EWR-SIN via TYO for under $500 return. I would pay with Chase UR points via Chase's site at a rate of $0.015 per Sapphire Reserve points (about 32K UR points total for the RT).
The transpacific leg is on UA and the TYO-SIN-TYO leg is on ANA.
I am a member of UA's Mileage Plus Program...not a member of ANA's mileage program, and no elite status with UA.
On Chase's UR travel booking page the trip is shown marketed by UA and marketed by ANA at about the same price.
A few questions (yes, I did research them online but found responses quite confusing):

1. If I book it marketed by UA, will I get full Mileage Plus credit for both the UA and ANA legs of the trip? If not, what would I get? What would I get if I book the same flight marketed through ANA?
2. Would there be any differences in flight change penalties based on which airline is marketing the flight?

Thanks in advance,
Protagonist.