How should I go about assessing homes in this list?  

This would apply to your unit.Your biggest concern with setting the rent should be the near future. 1) Your insurance is guaranteed to go up, probably dramatically.  2) You may get an insurance assessment bill to cover the CA Fair Plan losses.

See if they will give you an estimate of the assessment for the property.

You need to review the assessment record for your property as there may be errors. 

I have a property on the barrier island that I do not want to list on MLS but I am interested in connecting with realtors or investors who typically sell or buy pocket listings and may be interested in this property.

If you "need" to get five listings, you won't get them.

One of the most experienced offices has listed a property that I am interested in.

All brokers, realtors, wholesalers, etc... you need to check this list before you call anyone!!!!

I'm getting ready to list my first large property with 3 separate units (Main Unit, ADU, DADU) on a SFH.

I think it makes most sense to create a buyer's list, and then move to contacting prospecting sellers.