I may be wrong, but you bring to mind someone who posts off and on across various sites. Anyway, congrats on your accomplishments. I did the Oracle DBA certs, too, and they are not that easy.
From what you have already posted, my guess is that you are operating at a much higher career level than most all the posters who will read your questions. I think many 1099ers and w-2 S corp contractors have been inundated by off-shoring and corporate/lobbyist/Congressional supported visa tidal wave. Add to that the tech slump and financial system woes. But you seem to be functioning at a level where you can still call some shots. That's great.
The HR person's remark about can you keep nailing down contracts the rest of your life: She has a small point there. But if she is selling her company's "job security", tell her to sell it some place else. They don't sound like they will be in business this time next year. A CFO that thinks complex DBA work can be done by recent grads at 30/hr clearly does not understand the value you are providing. The managers seem like the type that will eventually drink the "desi/Jim Jones/Kool Aid" and end up wrecking their company.
These people at your company are taking advantage of you, even if unknowingly. You are going to have to nail down some type of hourly arrangement until you can move on to a better job. This can be your 1099, your S corp, an enforced agreement in your perm job that will limit hrs (good luck but it probably won't stick). Let's face it. Every OT hour you work free is just one less hour they have to pay someone else. If they have allowed you to work the hours you said (as a perm), I don't think they are going to back off any through the rest of the year. Neither would a coke addict turn down a free line.
Your company's main beef may be that allowing you an hourly arrangement makes it hard for them to justify not doing same for other perm. Ok, and I hate to suggest this, but locate a halfway-reputable DBA contracting co. in your area, take the deal to them, give them their 20% cut for an hourly arrangement, and work it this way until you can move on. That gives current employer "cover" with IRS and its other perms.
Is your CPA any good? Nobody I know in I.T. contracting or private industry perm jobs is getting 1.5 time for O.T.--have never heard of that except for maybe perm gov workers.
Just a thought for the intermediate to long term- Have you thought about nailing down a state or federal DBA job, then working some contracts on the side? This would provide a stable base for you, with very limited overtime, or at least the on-call would be comp-timed back in a given pay period (usually two-weeks). That's how it works in my agency (federal), and reading the federal worker web sites, seems to be the norm. These government agencies are absolutely fanatical about time-keeping and "playing by the book" on employee hours, whereas private industry just plays fast and loose with same. Once you get your security clearance, that adds a measure of job security (you do need clean criminal/drug/background/credit/references). And you will not see h1bs, cause, guess what, they are not eligible for clearance or, for that matter, even eligible for any federal (or most state) civil service jobs. You would need to discuss up-front what restrictions there might be on "outside" work, but I know some who are doing it. Go to USAJOBS site. This has been my approach, and it is working ok so far. But I run a very lean life style and understand that you have parental and other financial responsibilities.
I am older than almost every one else still in I.T. and have been through many recessions. We will get out of this one eventually. And there will (I think) be some push back against outsourcing/globalism/open borders, etc. Then your skills will blow past "marketable" all the way to "gold"
Obviously, only you can decide how to mix the superdba and superman roles. Problem with the superman role is that, ultimately, we are all human, and the kind of hours you are working will eventually grind anyone down. Probably to the detriment of your relationship with you child. Maybe not 7-10 years from now, when she is on her own, but for the short/intermediate term, yes.