Yes, you can do both in one day. TL and BB count as one of your WP entry tickets not your main theme park passes. For the main theme park passes, those are only counted when you enter Epcot, AK, DHS, or MK.
The way WP and more works, is say you buy a 5 day ticket with WP and more. You get a five day ticket to the main parks (Epcot, MK, AK, and DHS). Then you also get five entries to the water parks/DisneyQuest. You can use those however you want. You can go to TL in the morning and MK at night. Then you will use one park day and one WP and more day.
You may find that you don't need tickets to the big parks for every day of your trip because you may do only a water park and DTD that day. It is really up to you how you use them.
