Overthinking lock options for duplex (keypad or keyed)

[Warren West]

Would like some insight into the lock setup for my first duplex.  It has one common door in the back and each unit has its' own entry door in the front (so 5 total doors needing locks).  The common door in back is closer to the driveway than the front doors and offers relatively easy access, although it would mean walking through the patio.

I have a few things I've been considering (and likely overthinking):
-If I were to install keypad locks on the back common door and each entry door in the back is it unreasonable to not provide keys to tenants and have them only use the back door as the primary entry.  I don't want to have the expense of keypad locks for all 5 doors but if I could just install them on 3 doors and have the front two be deadbolted I think there are some pros to this.
-If I do choose keypad locks I've been looking at either the Schlage Be365 or Kwikset 913 UL, not sure which I'd want to go with.  I'd also prefer to use this option to keep things keyless and not have to give tenants any keys at all.
-Currently I am prepared to swap all locks to the Kwikset SmartKey setup.  I did see that they are only grade 3 and although it seems like a good neighborhood I don't want to take unnecessary risks.  I also figure with this I'll need to give every tenant 2 keys; one to the common door and one that controls their own doors.
-Also, read some advice about only using deadbolts and then closet knobs.  Is this secure and advisable?

Overall my goals are to have the most efficient system I can that minimizes how many keys I need to have and give to any tenants.