In the globals, try setting the smtp server to just:
do not add the port onto it.
$WAGLOBAL_Email_Server = "smtpout.secureserver.net" ;
In the mail_PHP.php file, change line 254:
$mailObj = mail($mailTo,$mailSubject,$mailContent,$mailHeader , "-f".$mailfrom);
$mailObj = mail($mailTo,$mailSubject,$mailContent,$mailHeader , "-f".$mailFrom);
In yours, the f in $mailFrom is not capitalized. PHP is case sensitive.
When setting the character set, utf-8 may need to be capitalized:
$WA_MailObject = WAUE_Definition("".($WAGLOBAL_Email_Server) ."","25","","","","UTF-8");
I have used 1and1 for sending emails by just leaving the smtp server setting blank, they are good about setting this in the php.ini file. The only real caveat I've found with them is the from address must be a valid address for your domain.
As far ftp accounts and number of websites, you will need to ask 1 and 1, I have no idea how many websites are included in a 1 and 1 business account.