I read an interview with Dalton on Screen Rant, and he said no one has approached him about a return in a season 4 storyline feature LMDs. He did not say he won't be back either, though.
He is encouraging fans to use the hashtag #HiveSurvives the same way they did #CoulsonSurvives.
I think that if he is brought back as an LMD that it should be as Grant Ward, not Hive. If Hive returns at all, it needs to be powered down a bit or given a known weakness. The invulnerable villain that can control any inhumans it shares the air with is tiresome and would just become repetitive.
I really think they need to move on from the Inhumans story focus. That isn't the only cause of powers, but suddenly that's all there is. Step away from Hive and Inhumans so it doesn't stick us with a cliffhanger before the movie comes out in 3 or 4 years.
Ultimately, I am more inclined to believe that the LMD is Lincoln, if anyone that we know who is dead (based on his comments about Fitz and Simmons not needing to lose friends). I think that it is far more likely to be Holden Radcliff. He's just egotistical enough to do that. I know he's excited to show it to Fitz because it will be a more secure replacement for the holograms.
Another option for next season: They make LMDs of the whole team for field ops, but they turn evil and it's SHIELD vs SHIELD.
Also, who is the new director. Coulson referred to getting orders from the director when they were trying to get Daisy.