Married, filing joint, both over 50, checking IRA contribution limits: AGI is 172,412, MAGI wks indicates MAGI is 144,543 (is that possible?) How much can we contribute?

To a Roth IRA or traditional IRA?

Both; want to put 6500 in Roth for him, 1000 in Roth + 5500 in Trad for her.  Is that OK?  Also, is it OK for MAGI to be less than AGI?

Yes, that should be ok. For the Roth as long as your MAGI is < $189,000 then you can contribute up to the max limit, $6,500 in your case.  For the traditional IRA, you can contribute the $5,500 but if you were covered by retirement plans at work your deduction might be limited. Please see below:

• IRA Deduction if You ARE Covered by a Retirement Plan at Work - 2018
• IRA Deduction if You Are NOT Covered by a Retirement Plan at Work - 2018 (deduction is limited only if your spouse IS covered by a retirement plan)