Questions about Items

[Amaterasu]

Another question in relation to the first, how much of a time gap can there be inbetween posting in the log, and in the IC theard.

So long as you don't use an item you haven't purchased (i.e. using a Vita Compass that you never bought) you can take any amount of time between purchasing and summoning an item. I myself have purchased a move over a year ago that Amaterasu has no access to ICly yet.

Also, any purchase that spends your available OM, including consumables, goes into your log, no matter how minor.