Hey Benoit,
I’m just about to launch my app for alpha users which has a lot of the same functionality, and then much much more. I have done most of what you’ve asked for, and it does take some time to learn, but it’s not difficult to implement. I haven’t built anything with Drag and Drop features like Trello but from my understanding it is possible. I also haven’t messed with fonts, but if I recall correctly you can install fonts in settings, and I wouldn’t be surprised if there were plugins for fonts.
Hope that helps.