I'm running a mini campaign within a normal campaign, which has a different DM. The regular DM has a PC of their own and we, as a group, thought it would be fun to let the DM really play their character and give someone else a chance to DM for a bit. So when I took over as temporary DM, I removed my PC (through shenanigans) so I could concentrate on DMing as its my first time.
However, I thought it would be fun to bring back my PC except as a doppelganger pretending to be them. I'd obviously make them act different, and the doppelganger would be trying to lead the party into danger and whatnot. But does the doppelganger get to use my normal PC's stats for rolls? We all have access to each other's sheets because its an online game so I think they would notice if I was using different stats/modifiers. But I don't want to do off-site rolls for the doppelganger!PC in case they get suspicious right away.
We're playing a D&D based homebrew game FYI.