#1) How can I apply the same transition to all of my slides, without going through each one individually?
#2) I am using the same title slide (to keep a consistent look) between the sections of my video. However, different text belongs on each title slide. Whenever I change the text on ONE of the title slides, it changes the text on ALL of the title slides, since I'm using the same template. How can I get this to stop doing that?
1) You need to create a slideshow with the media still in the project Media Bin, select all the photos/videos you want in the slideshow and then right click and select Create Slideshow. here you can set the default transition and transition duration as well as the duration of the photos. You can change the default transition in the Transitions window. Right click the transition you want as default and select "Set Selected as Default Transition".
2) To do this, right-click on the title in the project media panel and select duplicate. Then you can change each title separately.