Can you do this, potentially but typically it will be written that you need say a 2/3 or 3/4 or high majority to do this.

Using a commercial/DSCR lender means they typically don't need to be seasoned.

I would be willing to put 20% down. would this typically result in a Lower final cost since the builder doesn’t have to put up any of the initial investment or carry the loan for the build ? 

The pool, I can't speak for since in my market of Cincinnati, OH, pools tend to hurt values, but we only get about 2-3 months of use due to climate.Back to bed and bath, while typically more beds and baths can help value, if you are just cutting up the property and making everything too small to be useable and/or you have to walk through one bedroom to get to the other, you could very well be better off not adding it.  

With a typical LTR property @ 7% cap rate someone would need to buy with either cash for about 7M to get $500,000 cash flow or it's equivalent of equity if leveraged? 

For example, in 2024 if married filing jointly see table below.You could also do a 1031 exchange to avoid the taxes completely but have to invest all money into a like kind property of higher value. 

May not be typical but seems to be a great product.

Are there any examples you can provide please?

:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+, zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680, some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

Do you guys typically structure your deals with seller financing instead?