I went on the MLS and I saw a lot more houses than what he placed in his list.

Bring them a good deal (not listed) and take a finders fee as an equity stake in the property.

Because later, you can easily use it as your mailing list!

As far as your wholesaling journey, I would probably advise you to start off by buying a list of potential motivated sellers, skip tracing them and then cold calling them.  

They will provide you with a list of items, do them.

Have you tried listing it on the MLS?

I’m eager to learn first hand the wholesale process - finding properties, building a buyers list, ins and outs of contracts and networking with agents, flippers and investors.

Because later, you can easily use it as your mailing list!

I have no idea how much equity they have on the property.So say the property is listed at $500K, can you get a DSCR loan for say the 70% first position, and have the seller finance the 30% down payment in second position, all while they're trying to 1031 that property into another another one.Assuming it *is* possible, what would the benefits be for the seller, tax-wise or what would be the ideal strategy here for both buyer and seller?

Find properties such as duplexes, triplexes, and small apartment buildings on BiggerPockets Marketplace and local listings.