Hi,

1/ "All" here is all posts come with your filter. In this case, all tab here will total all posts from your categories: "Florals" and "Landscapes". And you can't hide this tab.

2/ You can try add more this code to Customize > Custom CSS to do that:

.penci-page-header h1{ color: #ff0000; }

Change color code ff0000 to any color code as you want. You can get a color code here

3/ You can try add more this code to Customize > Custom CSS to do that:

.portfolio-page-content{ max-width: 800px; margin-left: auto; margin-right: auto; }

Change value 800 to value as you want.

4/ Because the mansory layout will be display mixed the items inside it ( see some examples here ), so even you sort it by the way you want, it can be mixed again when use mansory layout. So, if you want to do that, I recommend you use portfolio "Grid" layout.

Also, you can try use plugin https://wordpress.org/plugins/post-types-order/ to re-order the projects.

Best Regards,

PenciDesign