As long as they hold on to the new property or as long as they 1031 each time they sell they will never pay tax and their heirs will get the property with the tax eliminated in the step up basis.  

Since I'm often painting at those times it is no extra work to go up on a ladder (or have my painter do it).By using LED bulbs I also eliminate the need for tenants to have to replace them because they last so long.

We need the cash to eliminate debt and improve this new property.+ improvements to this property would at best break even, and in the long term this neighborhood seems "safe" but not clearly on the upswing. + we have occupied the home for >2 years (after having previously rented it out), therefore it would qualify for capital gains exclusion. + the home requires some repairs.

Might want to check the EPA guidelines on lead-based paint removal/abatement/encapsulation:https://www.epa.gov/lead/evaluating-and-eliminating-lead-based-paint-hazardsAs a landlord I don't think you have a "do it yourself" option anymore.

Virtually eliminates Oregon’s no-cause eviction law;Imposes possible rent control Requires all fixed-term tenancies to continue indefinitely, solely at the discretion of the tenant;Requires landlords to pay for evicted tenants to move; andAllows tenants one year to file a complaint for any violation of the bill with 3-months rent + damages due to the tenant.If you live in Oregon, this is worth looking over.  

I would like a duplex or house with an apartment garage to eliminate my own overhead before making bigger investment deals once I am a licensed realtor (about 2mos from now).

Im finishing up a flip and will have 150k after its sold. should i put this money toward my primary residence mortgage and eliminate 18yrs interest essentially doubling my money?

I find making money eliminates any moral dilemma I may have.

It will also eliminate some buyers.  

It will eliminate the majority of buyers that will be willing to pay top dollar.