1. AdminCP > Settings > Options > Style & Language Settings > Show Instant Messaging Program Icons > No
2. You will need to edit the postbit template to remove the stuff you don't want. Here is an article on adding profile fields to your postbit -
https://vborg.vbsupport.ru/showthread.php?t=250418
3. Edit the template if you don't want to turn off reputation.
4. You could possibly do that via CSS but we would need a link to see the page.