Q.1. transplanting 4 0’clock flowers 2. Spray with Epsom Salt.
1. Planted some 4 o’clock seeds outside on July 24.
To date, they are growing…currently about 9 inches tall.
No flowers yet.
– Can I transplant these plants for winter?
– If yes, what procedure to follow?
1. Is it too late (September) to spray my lawn/flowers with Epsom Salt?

Regarding most of your questions, there is a link below that will take you to a couple of articles that will answer most of your questions,
Now, with epsom salt... It is safe to spray them at any time, however it is advised that you spray while it is cloudy, or at least not in full sun, as there is a chance that the plant may get burned, or show spots. I recommend using epsom as an additive to watering as well! Here are the articles that will help: https://www.gardeningknowhow.com/ornamental/flowers/four-oclocks/