What’s my best option to argue there.

I am on the lending side of things, so if you'd ever like to chat shop and options out there, let me know. 

Since you're not looking to make it a full-time career, you might consider passive investment options such as investing in real estate syndications - this GP/LP structure as a limited partner, allowing the GP to earn you a return allows you to invest in real estate without the day-to-day responsibilities.

I am a bit surprised that there are not more options? 

If borrowing against stocks is an option, do they have to be stocks held within the US and/or do Canadian stock investments count as well?

@Kamal Sukhija, The single member LLC option as been mentioned a couple of times. 

My lender is suggesting me to buy property under my name and then transfer it to LLC later as there are not many financing options available for LLC.

Be sure to explore all around the forums as well as many of the FREE tools that Bigger Pockets provides.I am on the lending side of things and am always happy to hop on a call to discuss loan options that are out there, even if not offered by my resources.

I have purchased one duplex using my own money and am looking to scale but wanting to leverage OPM or low or zero downpayment funding options. 

I would recommend working with a TK provider that has options for you to diversify in multiple geographical locations.