You are only adding complications and costs with the LLC with no upside  This is all assuming there’s been almost zero appreciation and you shouldn’t sell tax free while you have the chance. 

Is it better to keep adding equity by doing work on the houses while I'm renting them then refinance to recover the initial down-payment to reinvest into another property or to pay down the heloc?

Expectations for a higher standard of decor and theming has infiltrated this industry and those are the ones that do well.

Adding a washer/dryer to a $500,000 two-flat in Rogers Park could allow you to raise rents by $150/month, significantly boosting your ROI.8.

But with the added detail, option 2 would still be my least favorite. 

Most contractors here in California will charge their hourly rate and possibly ad on a smaller charge if they need an assistant.  

Quote from @Eduardo Perez-Borroto: Since the HELOC was not used on improving the home you cannot deduct the interest, nor use that to offset your capital gain.Would adding a battery bank system to my solar panels count as home improvement? 

It is great that you are thinking of adding to your portfolio.  

I'm currently renovating my rear unit and it has the perfect layout to split into 2 units by adding a wall and an additional front door.

I went back to the webinar through a different device and saw that they had also added a link to access his Gator Method for $2,997.