What type of level shifter will work in this circuit
Well, by the look of your circuit, you don't need to use a bi-directional level shifter for MOSI and SCL so, ditch the bi-directional level shifter and use a TTL-input-level-compatible CMOS buffer fed from a 5 volt supply. Now, SCL and MOSI will be 5 volt line voltages: -


One built from discrete parts would be preferred. I could learn more
from it and I could build it without buying new components.

Well, you could build one yourself but, with the loading of R3 and R4, you would need to make the pull-up resistor about 500 ohms: -

The above is an inverting level shifter so, to make it non-inverting, drive the gate via a compatible inverter buffer (plenty to choose from) but, then again, you might just as well ditch that idea completely and use the SN74LV1T34 (or a compatible device).
Alternatively you could do this: -

This means adding a local SN74LV1T34 (or a compatible device) in the sensor block area and swapping the 3.3 volt logic drives to feed sensor B directly.