Does anyone have any tips/ advice to help make sure my property will appraise for what I planned on based on my rehab?

How to Price the Condos: Do a reverse amortization schedule for a 30-year mortgage based on Room Rental Prices in the Area.

Spending on expensive upgrades is not the answer to improve your tenant base in this type of area.Keep the homes habitable, clean, and safe. 

That said, I am thinking about Wake Forest, Garner, Apex as frontrunners based on the fact that they are closer to RTP and have generally good schools.

For instance:If your area has many corporate offices or conference centers, you're likely to attract business travelers.Family-friendly suburbs with parks and schools often attract families.Downtown locations near nightlife are popular for groups and parties.Review Competitor ListingsSearch for successful Airbnb listings in your area and study their target audience based on:The language in their descriptions.Their reviews (guests often reveal the purpose of their stay).The amenities they offer (e.g., desks and Wi-Fi for professionals, cribs and baby gates for families).Evaluate Your Own SpaceYour property’s layout, amenities, and location may naturally cater to a specific audience.A cozy 1-bedroom apartment downtown might be ideal for professionals or couples.A 3-bedroom house with a yard might appeal more to families.Proximity to nightlife might cater to party groups.Experiment and AdjustIf you're unsure, start broad and monitor who books your property.

Is  this based on one of BP's deal analyzers?

Hence the lot on which the house resided was taxed at a 45% discount based on actual value, while the tennis lot was taxed at about 4 times what it should have been by value. 

I'm also based in California.

Based on the questions you are asking I think you need to spend more time listening to podcasts like Bigger Pockets and Bigger Pockets Rookie.

If you tell the IRS it is an expense, it is no longer income.W2 income does not use a 2 year average for your base pay!