One thing to keep in mind is typically a lender will not be able to reimburse you for labor you complete yourself on a flip. 

Would the person who takes on more labor to repair the property have greater preferred equity or is this usually treated differently?

I can say there are specific custodians we like to work with who are streamlined and smooth process and some who make the process a lot more labor intensive, and have had two investors using the same custodian and have one tell us we need to complete this form and the same custodian tell their other client that its a different form.

I suggested to them we could split the costs 50/50 of installing the electric, the garbage disposal, and the labor for installing it as I would be more comfortable having my guy do it.

I live in Florida but my family is from Portsmouth and I just there for Labor Day.

You don't know what material costs were, what labor costs were, or John's scope to flip the property. 

The purchase price, construction/labor costs, and ARV are all higher here in California than most states so I already have a high tolerance for risk and have the necessary liquidity to scale. 

Unless you need them installed for mortgage appraisal, recommend:1) A price reduction or 2) Small price reduction for installation labor and have someone pick up & store the mechanicals the seller provides.Otherwise, they will just get stolen again!

Labor, supply chain (we are on an island) and red tape: from offers and closing, to funding to permits.  

I came up with $385,000 to build for material/labor.