We haven't had any big change in scope, sold/purchased maybe 6 properties over the last 4 years but they fell under our existing LLCs, most of which are considered 'disregarded". 

Unfortunately, this has often led to a disregard for proper portfolio management, with attention diverted towards maintaining an image of dominance rather than fulfilling responsibilities. 

This may be easy enough for most states and their relatively simple tax regimes, but states like California, New York, Texas, Pennsylvania, and a few others have some quirks to them.For example, California makes disregarded single-member LLCs file a tax return, pay an LLC tax four months into the tax year, and potentially pay an LLC fee six months into the tax year based on estimated gross receipts.  

You're right, a CPA would be able to answer your specific tax questions, but I do know that as a single member LLC, the default tax status is disregarded entity.

It depends on if the LLC is a single member LLC or a multi-member LLC.If it is a single-member LLC, it is considered a disregarded entity and reported directly on your individual return.If it is a multi-member LLC, by default, it is considered a partnership.If there is no income or expenses(rare to happen), then yes, no requirement atleast at the federal level. 

I am beginning to invest in real estate (rental properties) and wanted to understand the benefits (or disadvantages) of holding title to a rental property under an SMLLC/Disregarded or as a LLC/Partnership. 

So the IRS calls this a "disregarded entity" and sees you as the real tax payer. 

Your LLC should have income since the leases are in its name and should be receiving the rent, not you.Single member LLC's are considered "disregarded entities" by the Federal IRS. 

You can elect to have a single member LLC taxed as (1) a disregarded entity, (2) a C corporation, (3) an S corporation.  

A judge may completely disregard the offshore ownership and directly grab the asset that are in his jurisdiction ie the real estate.So, if you have a stock portfolio or own foreign real estate, by all means, if your threat model justify the cost of a foreign trust and its trustee, then use these offshore asset protection trusts.