Code requires a cleanout at at the foundation wall (inside or outside, depending on your code), every 75 feet (in your area), but also at every horizontal change of direction, at the base of all waste or soil stacks and in many areas when a pipe comes up through a concrete slab.
In your case, I would definitely recommend installing a TEST TEE cleanout at each connection into/off the waste stack...so easy to install now...so hard to clear a drain later, ya know? Code would also require a cleanout at that extra 90 for the shower.
Finally, in my opinion, those cleanouts on traps are really more for cleaning and retrieving stuff from the trap...not for snaking unless there is no other alternative, OK?
Anyway, that's my take. I'm sure others will be along soon to share their thoughts here!