Hey, thanks for the questions!
1) Late submissions are fine! Just make sure you either (a) submit the game page to the jam before the deadline and change accordingly, or (b) keep in touch with me and send over your game page link so I can send you a late submission link.
2) No problem with long/experimental games - you're more than welcome to submit. I might not be able to finish, but I'll give it a good go.
Hope this answers your question!
- FSV