Voldri

You can change your URL (if you're using nulled,) in the conf_global.php file in your forum directory folder, usually wherever you uploaded the files at.
Otherwise if its a cloud package with IPB, you have to contact their support or use one of your free domain changes.

Really only one way to achieve this.
Go into the theme's html templates from the customization area in the ACP, search for ipsDataItem_meta ipsContained_container ipsMessageRow it'll be in the messagelistRow
<div class='ipsDataItem_meta ipsContained_container ipsMessageRow' data-ipsTruncate data-ipsTruncate-type="remove" data-ipsTruncate-size="1 lines"> {{if $row['last_message']}}<span class='ipsType_break ipsContained'>{$row['last_message']->truncated( TRUE )|raw}</span>{{endif}} </div> Delete the whole if/endif statement, save. Voila.

You'd probably need to make a php function and count() the days between checkin and checkout. 

Perhaps try running the support tool in the ACP > somethings not right

#acpPageHeader.cDashboardHeader { display: none; } Should remove it. 
If you want to change it, probably just go into the default theme edit html/css in the customization area and look for cDashboardHeader acpPageHeader_flex (in the html templates)
And just change the code after the <h1 class="ipsType_pageTitle">

You'll probably need to go into the plugin itself and search for that particular text area and remove it. It would be as easy as right clicking the plugin file and 'editing' it I would assume.

If you're a moderator of the forum, on the left hand side of the forum there's a arrow that looks like this

Click it and then click the forums dropdown and drag the "post feed" and "topic feed" to your sidebar on the left or right.