What can I do about my stepdaughters' visa situation in light of the recent ban on approvals for certain countries?

Vote GOP out in the midterms.

Thai citizens don't need Visas? Why would your Thai wife or half Thai children need a Visa ?

My husband's visa to come to the USA and live with me has fallen under this "Pause" too. The US EMbassy in Bangkok pretends like it's business as usual but for family based immigrant visas it's a perpetual nightmare with no end in sight. The cruelist part is that these are the people who have the most reason to be in America, jumped through all of the hoops and legal channels, and they're the ones screwed over and forcefully seperated from their US citizen family. It turns out families don't buy politicians the same way corporations do. They're expanding every nonimmigrant visa class to keep a pool of quasi slave labor, methinks. You could try to make your stepdaughters a tourist visa to visit family in the USA< but it may be denied on section 214b as too likely to immigrate as my husband's was. So I have to move to Thailand to stay with my spouse. Good luck!

My wife also passed her interview but due to the ,"temporary" ban we are in limbo too. Presently there are a few lawsuits pending to get it overturned.

I think you should plan to make other plans…at least until 2028…I don’t see him lifting the ban anytime soon…

Depends on the visa applied for. Permanent immigrant visas are on pause for 75 countries. Temporary visas (such as B1/B2 tourist, H-1B work, or student visas) continue normal processing. If the U.S. Embassy in BKK is stating it's under review then unfortunately that will be all the information you receive until approved.

Can't really help but from your use of the word 'fall' - I guess you're from the USA. You are clearly aware of Trump's clampdown on many immigration routes - my guess would be that's what's holding things up. In your position, I'd be contacting an immigration lawyer. Many of Trump's policies seem to have been over-ruled.