Re: Texarea Size
By editing the Activity Stream Reply to fit your theme 
This is what your looking to edit.
`div.activity-comments form.ac-form {
display: none;
margin: 10px 0 10px 33px;
background: #fafafa;
border: 1px solid #ddd;
-moz-border-radius: 4px;
-webkit-border-radius: 4px;
border-radius: 4px;
padding: 8px;`
You must go and find that Rule, or add it to your theme and edit it to how you like
