1) It is not yet clear but it seems that you will be grandfathered in at the time when the changes occur in regards to occupancy changes.2) Per AB-68:"(A) One accessory dwelling unit and one junior accessory dwelling unit per lot with a proposed or existing single-family dwelling if all of the following apply:(i) The accessory dwelling unit or junior accessory dwelling unit is within the proposed space of a single-family dwelling or existing space of a single-family dwelling or accessory structure and may include an expansion of not more than 150 square feet beyond the same physical dimensions as the existing accessory structure.

What kind of neighborhood is this (zip-code, A/B/C/D-class)?

@Sabri Isbikhene I know an investor that just picked up a single-family property in a B neighborhood near Columbus, Ohio for just north of $100,000 and just got it rented for $1,095 (tenant pays all utilities).

I am married with 2 kids ages 7 and 3, and currently in school for pursuing a BS in Project Management.

I would call this house a B to B+ property.

A, B, C etc.) 

Per AB-68: "(A) One accessory dwelling unit and one junior accessory dwelling unit per lot with a proposed or existing single-family dwellingR1 with ADU Owner occupancy : Owner occupancy has been removed till 2025 but what happens in 2026 ?

Thank you in advance.With what you described, your best bet might be to cite AB-5 and make them W2/salary you.https://en.wikipedia.org/wiki/California_Assembly_Bill_5_(2019)You will find a world of possibilities open up as soon as that is done.

The plumber replaced the iron sewer line with ABS but he left the old sewer pipe for me to dispose of (which we had not discussed but the assumption was would be removed) and did not jet the sewer. 

They now own Lot A, B and C.