Additionally, are there any other factors I should be considering when purchasing a duplex or triplex?

The unobstructed water views for both front STR units can be challenging to determine additional value compared to other 3-unit properties without views.

If you are looking to refinance the rate and aren't concerned with taking additional equity out on your property, then you should use a rate/term refinance.

Additionally, they may have in their contract that if the property is sold that their company will broker the sale through their own brokerage company.Lease Option Partnership Benefits- The property is purchased at a discount which creates instant equity at the start of the investment.

Since these accounts are in the business name, they don’t affect DTI, making it easier to secure additional funding.How fast you're looking to scale will determine the best approach—some investors go the business credit card stacking route for quick access to $150K+, while others secure business lines of credit for more flexibility.

I find single ADUs are mostly being added by people with minimal RE investment experience often without a clue as to the value that will be added by the adu addition.  

Interest rate on the home is 2.6%, so I don't want to pay down the loan with the additional income coming in.

There are also 'mezz' lenders (typically for larger transactions) who will cover up to 90% CLTV and require you to bring the remaining equity to the deal, and additionally there is Gap Funding in the form of unsecured personal debt.The latter can potentially be the most expensive option, but allows for true 100% financing as there are no restrictions for how to use these funds, as they are unsecured, and generally obtained through personal credit, income etc (since there is no collateral for obtaining these funds).

NEVER borrow from a 401K, you are taking pre-taxed dollars and paying it back with after tax dollars, you do not get to return the loan with pre taxed dollars, in addition, some 401K plans do charge interest and maybe even fees, and lastly if you get laid off for some reason, it is a distribution with all the "fun consequences: tax at the last dollar rate, and if you are under 59.5 there is also the additional 10% penalty.Personally I like the HELOC, however you can also sell stocks and do tax harvesting there to offset gains if that is an option

Ask whether or not the insurer is licensed as a foreign or non-United States (alien) insurer and for additional information about the insurer.