Ask the seller if they can offer seller concessions to help cover your realtor fee.

Keeping it friendly and low intensity is more likely to be successful.I recently offered to completely replace my neighbor's fence next to my rental and they said "No".

Investing in Wisconsin and Illinois is a great move—both states offer solid opportunities for multifamily and single-family rentals.If you’re looking to connect with like-minded investors or agents, I’d recommend joining local real estate meetups or REIA groups in the areas you’re targeting.

My offer got accepted for an investment property in Pennsylvania.

It's one project, that's more hands off and offers great returns. 

I didn't like the fact of calling up sellers just to offer sub to or seller financing.

However, if you feel you need their input earlier, you could offer to pay for their visit to walk the property with you pre-inspection.

What are the pros and cons of each, and which offers the least restrictions, flexibility and cost savings for my intended purposes?

While it may not offer as much diversification, at least with a syndication, you can review the specific merits of that particular deal.Also, the fund operator typically has different motivations than the syndicator.

With what you are planning to do are you going to write your offer in bitcoin?