I am trying to determine if forming an 1120 C-Corp or 1120s S-Corp will provide the best benefits?

Here's what I would do, Instead of putting both names as beneficiary with 50/50 ownership I would put the property in a Land Trust and assign your company and you as 50/50, or just name your Corp. or LLC as 100% beneficiary of the Land Trust.I know your not structuring this Land Trust for privacy reasons but a small trick I would suggest doing is naming the Land Trust after the owner of the property and use the property address number.

HOAs are like corporations in that they are required to have periodic meetings, this is spelled out in the by-laws, and to keep minutes of those meetings and budget discussions and written budgets.

Professional landlord" is not a tax term, so I am not positive about what your CPA meant by that.I mentioned a single-LLC setup but he said that that would leave my houses just as vulnerable since they exist in the same corporate entity. 

Even if the market does correct, the corporate job opportunities won't let that last long.

I'm neither a lawyer nor an accountant, but I recommend Googling "closely held corporation" and then asking your tax accountant how, if any, the proposed idea might impact your overall tax situation (https://www.irs.gov/faqs/small-business-self-employed-other-business/entities/entities-5: A closely held corporation is subject to additional limitations in the tax treatment of items such as passive activity losses, at-risk rules, and compensation paid to corporate officers.).I've read that when two closely held corporations owned by the same small group of shareholders do business with each other, the IRS sees a red flag because some people try using this approach to evade taxes.From my readings of personal finance articles, this additional scrutiny is based on whether there is an "arms length" between the two parties in a transaction. 

When you reflect on this issue, investors can invest with a large number of Real Estate Investment Firms that set up “shell company” Special Purpose Entity [SPE] LLCs, that tell the investor their money is at full risk and they can lose all, and if they invest in that set up and the project fails the investor has absolutely no recourse, no coverage from any other company of the sponsor and has lost all.Doesn’t it make a lot more sense to go with a Realty Sponsor who puts the full faith and credit of their firm and its 13 year history behind the separate project with a corporate guarantee showing they believe in the project, showing that they back the project, and stand ready to guarantee the project with their monies in the event of a bad result?

It stands for Delaware Statutory Trust and is a trust / pass through entity in which a sponsor (think big real estate investment corporation) buys institutional property (apartments, self storage, commercial, medical office, etc) and then sells interest in the Trust/Property to investors.

This is not to say that there are not difficulties when you have an entity (such as working with lenders), but I think an entity is necessary whenever you have partners.I would recommend an LLC over a C-corporation or an S-corporation. 

Currently I am working for the Zurich Services Corporation as a Risk Manager.