Since you have all kinds of clips on each of those tapes, your best bet would be to import one of the tape clips at a time and use the Detect Scenes... option by right-clicking on the clip in the media library.
PD will mark each time a new scene is detected and will give you a subfolder showing each individual scene as a separate clip in a subfolder "beneath" the main library icon. You can tweak the auto setting or manually detect scenes if needed, but the tool normally does a good job at the default setting.
The screenshot below is from PD14:
This feature only works in the library and doesn't actually affect the original clip, but you can still drag each scene to the timeline and PD will save you the trouble of trimming all unrelated content each time.
I suggest making one "master" project with all the scenes from the tape clip, then use Save As and give the new project an appropriate name like "Xmas 2000."
In each individualized project, you can select individual or groups of scenes that don't belong and then right-click and choose Remove from Library. that way you'll end up with only relevant clips for each project.
For projects about each child, you may need to be more creative and start saving the detected scenes as individual libraries rather than projects.
Basically, remove all but the "Kevin" clips from each tape clip then export that library as "Kevin Xmas 2000." Exporting a Kevin-only library from each tape clip will let you import libraries with all of his clips from all tapes later into a single Kevin project later on.
Click on the "?" at the upper right or hit F1 to bring up the PD15 help file for more details on using any of these features.