Each taxpayer who is an "educator" is entitled to the "above-the-line" deduction for "up to $250" each for Educator expenses. You would need to enter them separately...one for each taxpayer, not a total of $500 for one taxpayer.
For additional questions, please refer to the following IRS link for IRS Topic 458: Educator Expenses
IRS Topic 458 Educator Expenses
Yes, if they are both Educators, then they should be able to deduct a total of $500 on the return, each to be deducting only $250 each.
