I was wondering if you have the connector and pin details for those fuses 3, 10, 45, 46, 68. I'm doing exactly the same on my 325D (2008 but pre LCI) it has exactly the same fuse numbers as that for the heated and powered seats, so I guess it has the same fuse/junction box as the LCI's.
I've searched for wiring diagrams but they're all too old and use different fuse locations for the seats.
I've also read the excellent seat retrofit DIY on here, many, many times
all I'm missing is up to date wiring schematics.