The reason you're getting the bold is that Bootstrap css for the label selector is bold. So to change that:
li.dropdown-menu-form label, .dd-list li label {
font-weight: normal;
}
To add padding after your checkboxes:
li.dropdown-menu-form input, .dd-list li input {
display: inline-block;
margin-right: 10px;
}
To get your scrollbar correct, you can't tell li.dropdown-menu-form to have a max-height of 100px and overflow-y of scroll, because that's going to apply it to every individual list item with the class dropdown-menu-form. So, you could try wrapping your dropdowns in a div and assigning it a different class to which you can apply the max-height and overflow-y properties. (Just like you wrapped your dd-list).