http://www.shipbucket.com/images.php?di ... 20Witt.png
http://www.shipbucket.com/images.php?di ... ulwark.png
http://www.shipbucket.com/images.php?di ... 0OCEAN.gif
this gives you an idea for the LCVP's.
is your ship an command ship? then I would suggest S1850/SMART-L. otherwise: SMART-S or ARTISAN or something like that.
note the huge space an Mk 41 takes, space that could be halved by putting only self defence weapons (max ESSM) on board. this will also drive down the cost: those directors are expensive!
the CIWS is already very high, and so is your hangar. if you look at other LPD designs with hangar, you will see that the helocontrol is most of the time lower then the top deck.
note that your structure is already huge per normal standards, so why would you?