My plug (regular gasoline) is an M14 x 1.5 and 20mm in length. Not sure if the different engine types have different size plugs.

Other screws than you need to remove in step 1 photo 2/3?

Not sure I connected the blue antenna cable from the kit. It mentions on the product site as a "DIN Antenna Adapter With Phantom Power Supply", so my guess would be no (https://connects2.com/Product/ProductIte...).

Not sure I understand, the CTKSZ02 adapter kit mentioned includes a separate adapter cable for the radio antenna (https://connects2.com/Product/ProductIte...). This connector should fit in most after market radio’s.

Don’t know, could be a SCSI drive, there are 68 pins. I included a detail picture in the last step.

Here is one sold under the type code CT20SZ02. Looks like this type of connector is used in a lot of recent Suzuki models, so they should be available from other stores (using other names).