I saw that if you get an individual loan, you would have to rent out the current property and occupy the second?

I now have a HELOC and looking to repeat the process now that the new 2020 ADU laws made the process easier and removed the “owner-occupied” restriction.

You can only 1031 exchange long term rental "Investment Properties" and property that is used for business "Owner Occupied".However, since this is hypothetical, if the IRS allowed you to 1031 flip properties, then you would pay taxes at your capital gains rate (once you sold the last property and didn't replace it) on all the gain from all the properties and 25% on any depreciation taken during the the hold periods.

We str the upstairs and I’m considering converting the downstairs to residential to do the same.My business (in the ticket resale space) was occupying the downstairs before but now we have shifted to working remotely.

There are REOs that are in better condition than owner-occupied sales.

I would like to sell my rental properties on roofstock instead of via a traditional realtor since they are tenant occupied.

Number of units and whether you owner occupy are both important to know. 

I would at least do these numbers as if you are NOT an owner-occupier, even if you plan on house hacking 

The rear unit remained occupied until just recently when they purchased their own house.

I am not sure on what kind of financing I can get for the construction since this is a non-owner occupying investment property. any leads ?