Adding text under logo and change text under footer

Ok, I found 3. https://www.themesandco.com/snippet/altering-adding-footer-credits/

1. and 2. ?

The easiest way to accomplish 1 would be with the following CSS:

.brand.span3:after {
    content: "My text";
}

2 is more difficult and will need a link to your site. However, you’d be better off asking on the forum for the weather widget, not here.