There are things you can do to make your ST1 more comfortable for your personal needs. Most of us don't ride bone stock bikes. That said, you can't alter the bike's geometry that much. The typical cruiser bike is crank forward and so are many hybrid bikes.
Notice the angled back seat tube and crank forward. This geometry allows you to slam the saddle height for a more upright ride position and your legs still have room to pedal with the crank forward.
The ST1 has a more aggressive, sporting geometry, with a more vertical seat tube and the crank is more or less under your crotch. That means you need a higher saddle position to allow your legs room to pedal.
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You can purchase an offset seat post, allowing more leg room, but that really isn't going to give you a true crank forward geometry.
Add a riser extension and cruiser handlebars and??? Will it work for you? That's of course if your cables reach, but I don't think they will. The whole thing gets complicated, trying to change the geometry of a frame and rarely gets perfect. The ST1 is a very nice bike and can be customized for comfort, but if you really want an e-cruiser you may want to get another bike.
Good luck with it!