I still feel I need to learn more about the terminology and how to properly estimate rehab cost to be an effective wholesaler.

The angry message is much easier to face  if you use a voice-to-text transcription service so they come as readable e-mails rather than irate voices.  

The unit has been cleaned, but we can still smell the cat, and we feel the effects of the cat dander/urine. 

How will either scenario effect cash on cash return and IRR?  

Anyone know of the most cost-effective way to do this?

The most effective method for lead generation on the web is pay-per-click (PPC) advertising on SEARCH engines (google, bing).

If you're serious about wanting to get started, there hardly any more cost effective way to start your investing education.

In effect, I had a partnership, with my parents.  

Consider sending in a 9 X 12 envelope as they can't miss it.Unless you're mailing many hundreds, this can be very effective as it adds value to your service, beginning with "heads up" this us what your house looks like now.

A single member LLC has no effect at all on taxes, unless you elect special tax treatment.