Hi Petar,
1- To correct this, I recommend adding a custom class to that column as in this screenshot:

Then you can add this CSS snippet to (X > Theme Options > CSS):
.custom_class .mec-wrap .mec-event-countdown-style3 .mec-event-countdown-part2 {
display: none;
}
.custom_class .mec-wrap .mec-event-countdown-style3 .mec-event-countdown-part1 .mec-event-upcoming {
text-align: left;
}
2- You can use this CSS code to change the background color, the font color is already white and I don’t think it will be visible on the white background color?
.custom_class .mec-wrap .mec-event-countdown-style3 {
background: #fff;
}
3- That’s because none of your events has a featured image, you must assign a featured image to your events if you want to use the Carousel style.
Thanks.