Hello,
1/ use the next custom CSS code:
div.mobile-menu-content .et_b_header-menu .menu li > .nav-sublist-dropdown:not(.nav-sublist), div.mobile-menu-content .et_b_header-menu .menu li > ul:not(.nav-sublist-dropdown):not(.nav-sublist), div.mobile-menu-content .et_b_header-menu .menu li > .nav-sublist > ul {
opacity: 1;
}
.et_b_header-menu .nav-sublist-dropdown .item-link:hover, .site-header .widget_nav_menu .menu > li > .sub-menu a:hover, .site-header .etheme_widget_menu .nav-sublist-dropdown .item-link:hover {
opacity: 1;
color: red;
}
2/ By default, there is no option to change mentioned icons.
Regards