People mention that certain cards will be reprinted, but how many supporters from the E-card series were reprinted? Very few. 4/18 to be exact. Out of 35 supporters from RS-LM, 10 of them have been reprinted in HP-on sets. I think it's safe to assume that most of the supporters in this format will not be reprinted.
Usually, the reprinted cards haven't been niche cards like Fisherman or Desert Shaman either, usually generic supporters like Oak's Research and Celio's Network. Here is how I feel the supporters will end up.
Bill's Maintenance - Could be reprinted. It has been reprinted multiple times before and is generic, but there has been many new draw 2 cards.
Castaway - Very niche card. I don't see this being reprinted.
Celio's Network - Mentions exs, and would be overpowered if it can grab any pokemon DP-on. I don't see it being reprinted.
Copycat - Could be reprinted. Has been reprinted before. Generic hand shuffle, but might not be needed with Cyntha Supporter coming out in next set.
Holon Adventurer - Holon = rotated.
Holon Mentor - Holon = rotated.
Island Hermit - Kind of niche, but kind of not. This could be reprinted.
Mr. Stone's Project - I see this being reprinted because it's great for beginners. Sure, Roseanne is so much better, but playability does not equal reprint-ability.
Professor Birch - I could see this being reprinted, but could understand if it wasn't. It's effect isn't that great anymore.
Professor Cozmo's Discovery - There are so many draw 2 cards now that I kind of doubt this would be reprinted.
Professor Elm's Training Method - Totally gone since it mentions exs.
Professor Oak's Research - I could see this being reprinted. It's been reprinted multiple times too, so that gives it a good history.
Scott - Too niche. I don't see this being reprinted.
Steven's Advice - I don't see this being reprinted. It was only reprinted in the US made set, so that wasn't even a JPN set (that I know of).
TV Reporter - Could be reprinted since it was in Dragon Frontiers, but again, there are many draw 2 cards, and there is also Felicity's Drawing that does the same job as this.
So, to summarize, I feel the cards that will be reprinted are:
Copycat
Mr. Stone's Project
Yeah, even though I could see some of the above be reprinted, I feel Copycat and Mr. Stone's Project has the biggest chance to be reprinted. But you know, I don't even think their chances are that high. Roseanne is just a much better, newer version of Mr. Stone's Project, and Team Galaxy's Wager is a newer version of Copycat.