Have multiple funding options in the works because one might fail and you will need the back up to close on time.

I think your manager is failing you. 3.

For example, (for a normal buyer) on a half duplex your total monthly payment to own a 300k place would be 2484 whereas rent on that same unit is going to be 2100 to 2200. 

Quote from @Victoria Phifer: I don't recommend charging anything on a credit card unless you have total control of your finances and can pay off the balance every month.I charge everything I can to credit cards, but I pay the balance off every month, 100% without fail.

Regardless, you could hit up your local REIA and get the word out to local agents and wholesalers and start getting on their buyer lists.

If you win, they want you to win and they will set you up to bid high and fail.If you are talking about online actions, those come with a 5-10 percent buyer premium and often get ghost bid up and relisted until it hits their reserve.

This worked for me, I had the same situation with a HELOC but did a failed refinance a few months back and had a solid appraisal in hand.

You might be able to find a lot of this info online, on YouTube, here, etc and piece it together however as a busy professional I didn't have the time personally to try and fail - nothing wrong about choosing that path however I knew I didn't have time and I was in peace with hiring a coach to help me through my first deal, 8k is affordable in comparison with the 30,40,50k programs out there.

As a buyer this is something you should be able to identify based on your due diligence. 

While nearby multi-family duplexes might slightly impact the appeal for certain buyers, they shouldn’t necessarily lower the resale value if the house is well-renovated and priced competitively.