Looks like you have narrowed the choice to janome. I would check you have a dealer for servicing close to. You never know when they will be needed and you don't want an extremely long ride.
not sure what you mean by mechanical and electric. All these machines run on electricity and are mechanical. For free motion it is easier if the machine has a large throat.
Sorry this is as far as I can help now until I understand your descriptions. Too early in the day for my brain to work.