i am not an expert, but I am going to go with the white spot just being part of his coloring. Also, this action on the bottom of the tank is not unusual after being shipped and put in a new tank.
If he(i think) is hitching now, I think he'll be ok.
Of course, you could contact Dan and get his opinion, which I am sure is mch better than mine.
Nice video, by the way, I gave up doing pics of my dwarfs as I find it difficult to get a good pic of them on my cheapo camera!
Congratulations, you're a mama!!!!