Of the two, I like Rentometer a little better, because (it claims) it pulls data from actual "for rent" ads near your property, whereas Zillow's seems to be more automated and involve more guesses/assumptions. 

I have a full time job and the STR is my side hustle so I needed to automate everything I could.

If you outsource out (can be done cheap through automation) it could be a little better but I doubt that much for one car.if you're going to become a car rental you'll need a fleet vs just trying to do this part time to make some money.There are far cheaper cars you can get and rent out that would likely make much more sense.If you're flexible on car types you can get cheap leases that make certain cars extremely affordable and likely with little costs outside the lease.

Has anyone fully automated PODIO CRM and know of a solid and reputable programmer who can do it for my standards and needs? 

There are some tools out there, one in particular I can think of, that help to automate this process for you (online application which includes full spectrum of reporting - ie. credit report, background check, eviction history check, etc - and automatically sends reference requests off to prior landlords for them to complete; and if you need to deny an application, it allows you to use a standard decline application message for those applicants whose applications you won't be proceeding with).

In my state it is Patriot Properties and it's another automated system.  

(Is the trick with that to keep following up via a drip email campaign or automated texts or something, thus building and maintaining a relationship without investing time until they’re ready?)

I’m currently researching ways to automate my email responses.

Given that number, what percentage are ready to get sold, etc.It wouldn't solve wholesaling but it could automate a large part of it -- the search. 

You can use a service like Shomojo or one of their competitors that automates all of that and allows you to ask screening questions in order for them to schedule a showing for the time you want to show it.