Regarding point 2-
It’s now working, “the elastic slider” problem was that you’ve added an empty slide. i just added an image to the 3rd slide.
And for “Nivo slider” yes the images appear with the normal height of image, so if you want to use i advice you to add images of size 1350×400
Regarding point 3-
do you mean it appears like this image? : https://db.tt/4uGzPwUN