Sorry for not responding earlier - had a few issues this weekend that kept me busy. I'll PM my phone number, glad to help where ever I can.
The first time I did the swap, I used the 205 harness and tried to swap the 205 fuse box over - big mistake. The bulk of the issues were because I dont have the BGB for the 205, so I dont have all the diagrams for the secondary systems. I spent a lot of hours repinning the dash plugs and working through the fuse box, checking for proper connectivity. It was a mess. I ended up ditching the harness, then later on swapped over just the 205 fuse box in an attempt to free up 2" of space. I need a bigger engine bay!
The second time I used all 185 harnesses only, and re-pinned the 3 connectors for the 205 ECU, then went through the diagrams to make sure all the sensors were getting the proper voltage. Made the changes I listed before and it worked perfectly. So much easier. I made a little diagram that others have used for repinning thiers.
My last 3 harness projects have been more difficult, and have really taught me some valueable lessons - like keeping the wiring as simple as possible. For instance, I spent all weekend troubleshooting some weird s#&% on one harness without any luck. The engine is a 3rd gen 3SGE converted to turbo, the ECU is from a ST205, the harness is from the 3SGE (had to be lengthened and modified) and the car is a 97 Celica ST. I have a major issue with the ECU / ISC valve and troubleshooting has been an absolute nightmare since none of it is stock. A full weeked and the car is no closer to being on the road... very depressing.
When you leave the internals of the harness in tact, its one less thing to worry about, one more thing to rule out when there is a problem.
Just my 2 cents.