Would you allow a PC to simultaneously provide Skilled Assistance to 2 other characters that are Crafting the exact same type of Droid in the same place during Narrative Time?

Skilled Assistance is typically a Maneuver in Structured Game Time unless there is some reason that it does not make sense.

What is your opinion?

I wouldn't. I usually only allow 1 person to assist someone when crafting (though admittedly I might relax that a little bit when dealing with droids, since there's more room for multiple cooks in the kitchen at once), and if they're assisting someone, they can't assist someone else. At the most, I might allow the character to provide skilled assistance to 1 other character, and just regular assistance to the other (shouting occasional advice while focusing on the other project, etc.).

The Maneuver thing doesn't really apply; it takes several hours to craft a droid, at best, and if they're providing skilled assistance, they are assisting for the full duration of that time (I would again downgrade skilled assistance to unskilled if they were only there for part of the time)

Sounds like a good reason for there to be Setback on the check. I would consider allowing them to provide Skilled Assistance (contribute either their Intellect or Mechanics skill) to both, but both checks would receive at least 1 Setback due to the PC being distracted.

Now obviously if this becomes a regular thing then i'm going to start having discussions with the players. I don't want this to be a every encounter, every hyper jump thing. BUT if its thematic like "We have got to crank out as many as possible before some plot thing happens" then thats cool as a one off.