So here is my story, my first bad experience as a landlord.Bought a duplex, moved in to the 2nd unit, did a lot of upgrade in the house to rent out the 1st unit to a family.

If your plan is to have the current owner repair the foundation along with other upgrades, one suggestion is to complete the renovations during the escrow process and only close if the repairs are executed as drafted in the contract. 

Upgraded electrical using an electrician and general updating.

I can see what is selling fast, what is sitting, what upgrades they have or if they’re in bad shape, etc.

Upgraded shower with 2 shower heads and independent temperature controls.

You can buy them or upgrade to a PRO membership and they will be included with your membership.It's important to learn your state/local laws and stay on top of them so you can refine the lease and operate within the boundaries of the law.

And what upgrades are this to the property. 

Since you live in it you would know exactly what it needs, in repairs, actually  take a good look it may need upgrades, sounds like you may be in an older part of Rancho, knowing the area's, I would say that's about average Market price.

While it works in theory to renovate one unit at a time and "upgrade" the class of tenants... in practice, the presence of the existing tenants will make it difficult to get and maintain the upgraded tenants in the single unit - despite the unit itself being upgraded. 

Each year we invest in a little more of an upgrade that we do ourselves over the Winter.