An engine block (including transmission) is light compared to batteries. Maybe a small car with a very limited range is lighter, but not for something useful. Electric cars are typically significantly heavier than their ICE counterparts.

100km is not a useful range. Remember that for best battery life you really need to only charge to 80%, and and never let the battery get below 20%. Now cut that entire range in half for cold weather. You are now down to 30km range that you really can use. That is round trip range unless you really have chargers everywhere you might go.

The average US commute is 40 miles or 65km. Though given you are using km you probably have a shorter distance, but even still your 100km car is cutting range too close for comfort for most people. (and you probably have better access to transit, why not get rid of that 100km car completely)

I don't know how to compare manufacture emissions. I do know that metal shaping has been optimized a lot, while I would assume as new technology modern batteries still have a lot of room for improvement (the older batteries probably not), so I wouldn't trust a comparison if you had data.