A single definitive paper, or an initial manuscript and a followup?
Regardless of your elaborate schemes, you will always need to take into consideration that you cannot "sell something" twice.

If the only novelty that you present in a second paper are additional experiments (and deriving conclusions from these), then you must never ever state something different as a contribution of the paper. And in many fields, this would be quite a weak contribution, basically only leaving your schemes 1 (conference+plus extended journal version) and 3 (single publication) as realistic, unless you want to settle for a very weak venue for the second paper.

Slicing your work is also frowned upon in academia, for several reasons. First of all it looks as if you are trying to inflate your CV. If it makes grasping your overall contribution harder, it should also be avoided. Also, there should always be some scientific reason for splitting up your work. For example, if the target audiences for the two parts of your work have a very very limited overlap, then splitting up your work may yield a better service to the community. If the parts of your work are mostly interesting in isolation, and actually only of interest to few people in their combination, then splitting up the work is also sometimes the best way to go. And finally, if the underlying techniques of the two parts of your work are so different that publishing the two parts together would lead to a paper that is only readable by the very few experts that have knowledge about all techniques, then the split may also be justified. In all cases, you have to reference your other work and explain the differences in contribution.

In some fields with published conference proceedings with page limits, it also became customary to to leave out some additional information in a conference paper and writing longer journal version later. This is ethically OK because the journal paper in some sense replaces the older paper. This seems to be precisely your "scheme 1".