I recently purchased a fixer-upper apartment for $500k (20% down with a 2.65% for 10 years, then adjustable) and spent a substantial amount of my cash holdings on an ~$80k renovation. 

If the price is too high investors won't want it and some owner-occupants won't want to be someone's landlord if there is a substantial amount of time left on the lease, and others might not qualify if it's a low money-down owner-occupant loan and the buyers need to occupy it by a certain date.

@William KellySounds like they called your BS and want you to substantiate your significant price reduction which you cannot.

Sure, the most important aspect of real estate is to do it, but I need more substantial guidance.

I'd gotten a pretty substantial raise for my job and we went out to celebrate and I brought REI up again. 

Normally you need some type of documentation to substantiate the reason for the violation, but this varies from one HOA to another.

@Aubrie Caton in addition to the aforementioned banks, America First Credit Union was also doing HELOCs on rental properties as of about a year ago (I don't know if they're still offering them or not).As you probably already know, HELOCs are usually variable rate, and rates are increasing (and will likely increase substantially in the future), so it's important to be clear about whether there is a maximum rate the HELOC can go to, and what that rate would be....Once you know the maximum rate, you'll want to run a "worst case scenario" financial model where your HELOC goes to its maximum rate. ...If an investor isn't basing their decisions on worst-case scenario financial models where adjustable rates max out, then they're risking a 2008-style disaster where their formerly affordable monthly payment balloons into an un-affordable payment as rates rise.Good luck out there!

Another consideration is if the property doesn't sell for what I'd like I don't want to be missing out on the rental income, which is substantial.

I'd offer them a substantial amount of money to leave.

If there is a situation in the future where the losses would be helpful - say one of the properties has significant rent increases and starts producing some substantial taxable income, or you sell a property at a gain, - then no reason you can't implement a cost segregation study on one of the originally acquired buildings in that later year.