What if production | LAMP already installed &... ...

hi,
i have LAMP installed... php 5.4 and mysql 5.5...
and also Webmin, Dovecot, Sendmail....and Roundcube database

what happens if i install CWP in this situation? any issue?
it ignores those installations and automatically retrieves any info by domains, users etc. etc. ?
and if i don't want to use Postfix and continue with Sendmail, is this possible?

then, a really important thing which could be amazing:
a domain expiration reminder by email and a billng module would be wonderful...
is already feasible now in some way or could be a feature to add soon?

thank you
best regards 

its suggested to have clean installation with cento minimal!

you will need to edit configuration of the server to use other service

there will be tons of new addons available in newer releases.