What should my wife consider when applying for a B2 visa to the USA?

# US B2 visa application concerns

My wife is applying for a B2 visa to visit the USA. 5y married to EU citizen, >10y of international travel with many trips to Europe, multiple Schengen, UK visa and a Canada visa, 550k in her bank account, owns property in Thailand, 20y Thailand-resident husband reliant on her for visa. I guess her being a housewife is suboptimal, but decent profile otherwise. Still, some questions:

1. She is insisting on doing the interview in English while I think she should go for Thai. She's at a B2 level: she searches for words, makes mistakes, etc. but can generally make herself understood. Thoughts on English vs. Thai for the interview?

2. She isn't great at remembering loads of little facts, and gets nervous speaking to officials, and doesn't understand what the underlying concern of questions are. Although of course she won't have memorized a description off the internet, I'm still worried she'll sound rehearsed. Of course we are doing mock interviews, but she has seen me naked so I don't impress as much as a visa officer would. Anybody have experience, and how much of an issue this would be? Any recommendations? I've seen these former visa officers offering mock interviews for $500 but that seems a bit over the top to me.

3. One could argue rejections increased to 27% since the current administration took office (FY2025 stats mangling). Has anyone got some real data on this?