[Mooff]

1. Not a file. That's in the php widget code, close to the bottom.

2. I'll post code for both sections and categories, since i'll link that post in the FAQ.
How to show only articles out of specific sections or categories:

for sections
find:

        WHERE
            node.setpublish = 1 AND
            node.publishdate > '. vb::$db->sql_prepare($time) .' -34560000 AND
	    node.publishdate < '. vb::$db->sql_prepare($time) .' 
        GROUP BY node.nodeid
        ORDER BY node.publishdate
        DESC LIMIT 20');

replace with

        WHERE
            node.setpublish = 1 AND
            node.publishdate > '. vb::$db->sql_prepare($time) .' -34560000 AND
	    node.publishdate < '. vb::$db->sql_prepare($time) .' AND
	    node.parentnode IN ( 4, 5 )
        GROUP BY node.nodeid
        ORDER BY node.publishdate
        DESC LIMIT 20');

For categories

        WHERE
            node.setpublish = 1 AND
            node.publishdate > '. vb::$db->sql_prepare($time) .' -34560000 AND
	    node.publishdate < '. vb::$db->sql_prepare($time) .' 
        GROUP BY node.nodeid
        ORDER BY node.publishdate
        DESC LIMIT 20');

replace with

        WHERE
            node.setpublish = 1 AND
            node.publishdate > '. vb::$db->sql_prepare($time) .' -34560000 AND
	    node.publishdate < '. vb::$db->sql_prepare($time) .' AND
	    category.categoryid IN ( 31, 1 )
        GROUP BY node.nodeid
        ORDER BY node.publishdate
        DESC LIMIT 20');

Can be combined of course, if you want that.
Be careful not to miss the AND part
In the Brackets the sections-Ids/ categories-Ids you want have to be included.
In your case it would be ( 144, 145, 149 )

In general you can see the fitting ids in the links which lead to the section or category:
For example:
/content/category/31-esport.html
Category esports on our site has the ID 31.

---- category/section part ends here - in case you followed the faq link ----

3. In the nivo-slider_uf_theme.css file

find:

.theme-uf .nivo-controlNav a {
    background: url("nivo_slider_sprite.png") no-repeat scroll 0 -30px transparent;
    border: 0 none;
    display: block;
    float: left;
    height: 22px;
    margin-right: 3px;
    text-indent: -9999px;
    width: 22px;
}

replace with

.theme-uf .nivo-controlNav a {
    background: url("nivo_slider_sprite.png") no-repeat scroll 0 -30px transparent;
    border: 0 none;
    display: block;
    float: left;
    height: 22px;
    margin-right: 3px;
    text-indent: -9999px;
    width: 22px;
    top: -120px;
}

The top value is new. Modify that to whereever you want it.