Hey there guys, now I know this isn't what you were expecting, but I have new projects to complete, and a sequel to my story is not one of those projects, nor is any new chapters. However, the recent comments have concerned me to a point that I went through them and threw together this little continuation to hopefully answer some of your questions you may have.
What are Applejack, Twilight, and Rarity doing at the end that they are too busy to be with Rainbow Dash? Well, this question has a simple answer, they were trying to help their friend for the whole story and fell behind on their work! Twilight was straining herself to try and find an answer, while Rarity and Applejack were apart of the search parties, and not to mention the fact that this sequel takes place RIGHT after MLD. So they also were trying to get Rainbow back through out those fifteen days said in the original story. So they are all very behind on their work, they just didn't want Rainbow to ask them why so they wouldn't of had to tell them what happened and risk resurfacing her memories.
What are the repercussions of him coming through the portal again? When Rainbow Dash left the note for her dad, she was told by Celestia that her powers must be removed for the portal to close. Rainbow charged the note she left with some of her magic she had left, thus leaving the gate open. However, she also said that once the energy ran out, the portal would close for good. Being that Dad chose to go through the portal (Spoilers, sorry, read the end of the last chapter if you didn't know this, and I mean the VERY END), the last of the energy was consumed and the portal was closed. Whether he wanted to go back or not, it doesn't matter. The two worlds are cut off for good, nothing will come through them again (so all of you who said Celestia can cram it, then you guys are victorious).
Is dad a pony? No, that is over done and I don't like it. Sorry those of you who are fans of it, but a human is a human, and a pony is a pony. Can't change that in my world.