"My Mom shouldn’t have taken anything in 2025 for my Dad, correct?"
Correct. In 2025 there was no longer an inherited IRA that would be subject to beneficiary RMDs. Even if the transfer to the IRA in your mother's name did not take place until 2025, she would still be treated as owner for all of 2025.
The fact that only one Form 1099-R was issued showing the combined amount of the RMDs suggests that they are treating it as one IRA account containing two CDs.
"that TT radial button asking if it was an inherited IRA threw me off because technically she *did* inherit it. "
Yeah, that confuses everyone who encounters this situation. TurboTax really shouldn't be asking this question at all for distributions from traditional IRAs and should just go by the code in box 7 (code 4 indicating a distribution to a beneficiary of an inherited IRA, code 1, 2 or 7 indicating a distribution from an owned IRA).
"I am now concerned about your statement that my Mom should have taken an RMD in 2025 for the IRA she inherited,"
By that I meant the account (or least the CD) that is now hers and no longer your father's. You said that two RMDs were taken in 2025, so I assume that that was one for each of the CDs, which is all that was necessary. Based on what you have said, your father's last RMD was completed in 2024.
