However, it allows you to use the vacant rents of 75% market rent as an alternative income to help the borrower to qualify.Happy to connect and assist you in your real estate investing journey.

Has anyone found a more cost-effective alternative that can match CoStar?

The alternative is to continue accruing 2-4 units along this well-trodden path. 

I’m current of looking for alternative quotes, but not looking promising. 

Alternatively, you could get the appraisal done, let it get called out and then have a conversation with the bank saying that this is all that is needed and with it is a full contingency release.

If you received a basis step-up at dad's date of death, you may be able to sell with little to no gains, and then choose to invest those funds in an alternate property closer to home, if desired. 

In addition, there are alternative rent models (STR, LTR, rent by room, etc) that can create better cash flow than the traditional LTR model.RE also can benefit from value adds.  

Are there any alternative strategies or adjustments I should consider? 

If you are currently renting, I don't see any alternative aside from house hacking where your monthly living expense can be turned into an investment. 

Ultimately, if your CPA is shutting you down on this, without presenting alternative options, it may be time for an upgrade.