Just read through this post, you seem to have alot in good order and its great you are doing research on things before progressing further. I do however wish to give you some guidance on the crocus clam...
I have a Crocus clam (also known as a Boring clam as they Bore into liverock). In most areas its illegal to seel them as they are heavily harvested and easily damamged. (mine came through on import by accident as a maxima).
Inspect its foot. If its damaged then its likely to die within a few months as its extremly sensative. Inspect its shell. If theshell is worn downthen its a wild one and probably caught illegally (i would enquire as to the legality of importing Crocus clam inyour area). If the shell has prominant riges on it then it is highly likely to be a captive bred one as these are not allowed to bore into hte liverock and thus wear away the shell.
Lastly, PC lights wont cut it. I have a blue crocus clam under 700w of halides and its lost its fantastic blue colouration and turned a sort of browny/blue. I know thati need to increase the light by anothr 300w or perhaps change the current 300w of 20k lights to 10k and give me a full 10k light @ 700w. Whilst the clam "might" live, it will not keep its colouration.. when its young it might be ok as they dont require as much light but as it grow its become increasingly dependant on light adn you will eventaully run into trouble.
Crocus clams are probably one f the highest in demands of light requirements.. maybe even moreso than maximas.
Here is a piccy of mine.
Piccy when 1st introduced.. A lovely blue/green colour.
And not about 6 months later.. (when 1st introduced it was under 400w 10k its currently under 700w 10 & 20k). even with the increased lights its still lost alotof its former colour.
. Ill be lookig forward, to seeing your tank progress throughout its stages.
/www.coralfanatics.com/zoanthids.html