I've seen a playable probe droid done in Bantha55's Hoth: Empire Strikes Back map. But from what I could telling playing it, it was just a normal soldier class with the probe droid model applied to it. I'm guessing the reason why trying to have a remote droid-style probe droid on one of the main 2 teams causes the game to crash has something to do with the shell for the class selection menu and/or maybe something to do with the hover physics of the remote droid. That might also be why only bots on local teams can spawn as a remote droid-style probe droid like on the Chain Isles map for BF1. That's just my guess though after attempting several times to get the Probe Droid playable. 
As for XSI, I haven't had much luck with it in the past. Complete noob with XSI (I'm more of a Blender user). Even if I could do something about it in XSI, I still have the issue of the exporter only exporting 2 animated bones of the skeleton (found that out while I was trying to invert the 9-pose fin animations of the republic & imperial fighter tanks to be like how it was in the 2002 Clone Wars video game so I was only able to have one working fin on those tanks
). Might be unrelated to what you're suggesting in XSI, but that's an issue I feel like might crop up or have something of similar consequence on my end.

As for XSI, I haven't had much luck with it in the past. Complete noob with XSI (I'm more of a Blender user). Even if I could do something about it in XSI, I still have the issue of the exporter only exporting 2 animated bones of the skeleton (found that out while I was trying to invert the 9-pose fin animations of the republic & imperial fighter tanks to be like how it was in the 2002 Clone Wars video game so I was only able to have one working fin on those tanks
