This is an idea of the project ...
First screen would have:
Choose background image and saved cards. (This is front of book). i.e. animated background might be snow falling with their photos on cover.
2nd screen would have:
uploaded video, images, or take new photo or video choice
text input with choice of font color, font style, size
picture drawing with choice of color
3rd screen would have:
send to email, text, etc.
Output would have: (when they open file):
video would come first with images if added (max 2).
followed by note
followed by drawing with signature
all would show with background music selected.
It is very similar to to Vlix holiday cards except the output would look like a storybook with flipping pages.
Front would have selected photos with text (To, From, Title)
Page would have video with play button, music, images and video
Next Page would have note
Next Page would have drawing and signature
Maybe you can develop the app without any graphics, etc. Just the buttons and screens and tables to save info to for saved items. I can work on the design.
So, the program would just have buttons to lead to each area but most importantly, the saved file would have the audio, video, storybook template, text and note(letter written) content?
I would work on the backgrounds to choose from and graphics.