The shadow comes from this CSS:
article.post::before, article.post::after {
content: '';
top: 19px;
height: 15px;
position: absolute;
z-index: -1;
background: transparent;
width: 50%;
box-shadow: -4px -4px 15px 1px rgba(202,207,214,0.75);
}
So it applies to any before element on an an article
So now you need MORE CSS to remove that style from the widget:
.widget article.post::before, .widget article.post:after {
box-shadow: none;
}
For the icon alignment you will need more CSS to adjust it for the Menu list:
.sidebar .widget.widget_nav_menu ul li::before {
top: 5px !important;
}
I really don’t like having these conversations with you as we want to help all our users achieve their requirements, but as usual these requests are all Custom development, and they seem to be a lot of customization requests on top of existing customization requests. Which in turn means more time spent by us ( and you ) trying to make things work.
I would recommend that you pin down your design first and then ask for help, as constant changes is just a waste of our time and yours. You may also want to consider you have raised almost 400 replies in 8 months in this forum. The time you must spend here may be better served taking a course in CSS.