The capital required for Denver, and limited cash flow makes it a tough market to get your next one.

I'd strongly recommend against a single family home and only target properties with at least 2 units otherwise it'll be difficult to cashflow in this high interest rate environment unless you plan on using a large amount of liquidity in the purchase.

As always, DYOR (Do Your Own Research) The area has a mix of stable, long-term residents and rental demand—especially with Section 8 tenants—but it does vary block-by-block.Key things to consider are Rental Demand, Property Condition and Management (a local property manager can help navigate tenant screening and city requirements)It’s not as bad as the headlines make it seem, but success here depends on buying right and the right property manager.

I also highly recommend being represented as a buyer. 

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

In my experience in MO, land bank properties are very low priced (these are generally properties/parcels that weren't sold at the tax auction), but they often have significant tax liens on them that must be cleared in addition to the "sale price" AND they require a significant amount of rehab in order for the properties to be inhabitable. 

(ii) Can anyone recommend an agent in the Philadelphia area who specializes in apartment buildings? 

I highly recommend hiring an attorney, at least for your first time.Some attorneys specialize in evictions.

have a rental (multi family 2-4 units) needing major rehab. interested in learning what work can be learned/performed easily and what needs to be hired out to a contractor. recommendations for learning resources for DIY rehab (good youtube channels, etc) would greatly appreciated!

Would you recommend the route of a first lien HELOC based on the above situation and information?