I don’t know which ones you had problems with but it’s worth noting that some automatically echo and some don’t.
<?php user_profile_link(); ?>
<?php echo get_user_profile_link(); ?>
get_anything then you have to echo them yourself, if they don’t have
get_* then it’ll echo on its own.
[Edit] Also remember most functions don’t need a $user_id passed as parameter but won’t work in this case unless you do pass it.