Education

Yes.  You can add both of their 1098-T's on your return.  Unless she has scholarship income that was used for things other than eligible education expenses, then there is no need to enter the form on her return. They are not eligible for any type of education tax credits when they are claimed as a dependent on someone else's return. The fact that he entered the form on his return does not affect your ability to claim an education credit for his tuition and expenses. 

As the parent claiming both of them, you can claim the American Opportunity Tax Credit if you qualify and they are in their first 4 years of higher education. If they are further than the first 4 years, then you may be able to claim the Lifetime Learning Credit. 

The qualifications of the credits are below:

American Opportunity Tax Credit.

• Available for the first 4 years of college
• Max amount is $2,500 per student
• Be enrolled in a degree or credential seeking program
• Not have a felony drug conviction
• Be enrolled at least half time
• cannot be claimed as a dependent on anyone else's return. 

 Lifetime Learning Credit

• You can take this for an unlimited number of years
• Twenty percent of expenses up to $2,000
• Non-Refundable meaning this can reduce the amount of taxes you owe, but if your tax liability is less than the LLC, your tax will be reduced to $0 and the rest of the credit is lost. 
• Cannot be claimed as a dependent on any one else's return