1/ Please read this article – https://xstore.helpscoutdocs.com/article/89-product-images
It is recommended to use a graphics editor and prepare product or post images (make them the same size) before uploading images to your media gallery.
2/ Where you can’t change the font color? Provide an example of such an element.
Lightshot Screenshot tool https://app.prntscr.com/en/index.html makes screenshots and generates links then you can provide links of screenshots here. Or you can upload ready screenshots into your media library and provide us with URLs.
3/ Edit page > https://prnt.sc/3xRoAvAoIzGj
4/ I’ve disabled Header overlap, in Theme options > Header builder. Please check now.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.