@Tam Nguyen I would start off by saying you've got a good solid foundation on how your structure should begin to be built out (I have a very similar structure), so good on you!
For my sake, I'm going to use "Holdings LLC" (for ABC), "CA LLC" (for XYZ), "OOS 1 LLC" (for Subsidiary A), and so on...
I would keep Holdings LLC as anonymous as possible, which I believe is your intent, since that is where all subsidiary LLCs land and adds another layer between you and the rentals. Then I would choose the "business name" you want to operate under, in other words, the name you will want to put out into the public, and perhaps brand and have recognized amongst tenants and vendors with whom you may conduct business. Let's say it's "Sunny Acres Properties". You then file a DBA for each corresponding LLC, in each state (but more specifically County) where each respective property is located. Counties tend to oversee DBA filings, but this depends. ("It Depends" is something we use daily in the legal industry :)) This does 2 things: 1) keeps your true operating/holding company anonymous, and 2) puts your operating name ("Sunny Acres" for this example) out to there as the way you represent yourself to the public. The reasoning behind a separate DBA for each LLC is because each state and county may have different guidelines to filing, and you will want to be on the up and up in each jurisdiction in which your properties are conducting business.
So Holdings LLC would not have a DBA, but let's say CA LLC is in San Diego County, I would get a DBA for CA LLC out of San Diego County. Then a DBA, using the same DBA name used in CA LLC, for OOS LLC (let's say that's in El Paso County, Colorado) out of El Paso County in Colorado. And so on...
I have a legal/asset protection background, so I'm not sure what (if any) tax implications this would pose, but I have a similar set up for one of my out of state LLCs and there was no impact. You should confer with a qualified, experienced CPA (familiar with each respective state) as to any effects.
Does that help?