While I agree with above posts, I feel like they could've added more constructive suggestions. If I was dreferr I'd probably be confused as to how I could improve from those comments.

Yeah the animation was dodgy, and the times when they didn't move were unusual, but I think you're at a really good place with your animation - a really good launching pad, if you will. Keep trying to improve it, learn the basics of easing and physics in animation, and take your time with it. Really subtle movement from the minifigures' bodies can help discussion scenes flow, and having occasional arm movement can help too if emphasized the right way. However if the characters stand completely still while talking it will come off as lazy and unbelievable. It may be easier to sync those mouth animations without movement, but without movement from the minifigure it's not going to come off as enjoyable.

And while I think the mouth animation was dodgy as well, for some reason I feel like the style is somewhat acceptable. It comes off as it's own kind of thing and I don't really have anything against it. Maybe it's not my preferred style, but I don't know what I would suggest about improving it other than syncing it better.

As for the joke - I don't know what I can say there. I didn't find it too funny but I'm not sure how I would've improved it, so I'm afraid I can't be much help in that department.

Just keep doing what you're doing and take as many opportunities as you can to improve. You'll have even better animations and more fun doing them!