UR don't transfer to ANA nor JAL so your plan won't work there. UR do transfer to partners of both airlines that allow for redemption when Saver level award space is available.

When evaluating costs of 1-way tickets you'll get an overinflated valuation as 1-ways are generally much more expensive and can even be pricier than a return ticket. If you want a realistic valuation look at the cost of a return ticket and divide in half.