Newbee Questions

Hi All,
 
We just bought a stock of 30 MEOS diapers in the unbleached.  Our baby is due in 8 weeks so we are preparing.  I used these diapers with a family I used to nanny for and loved them (more so than other brands I used with other families).  Therefore I am confident in my choice and we bought a large stock up front.
 
I am a little unsure how many times I need to wash them before first use though!  I've read everywhere from once to ten times!  My understanding is that the washes are needed with the unbleached to remove the natural oils.  But my question is, if using them with a newborn and I am planning to change them like hourly I don't really need them at their maximum absorbancy right away so is it safe for baby to just wash them once to start.  Will they then continue to remove the oils as I wash them every other day after use?
 
Another question.  I was planning to use Tide Pure and Gentle. Which I realize is not by any means pure and quite unlikely gentle.  I'd prefer this over regular Tide (no perfumes etc).  But, does this work as well at the regular Tide to remove stains/smells?  Since I plan to do the extra rinsing etc I am not too worried about not using a "natural" detergent which from my research seem to not work as well or are not actually "natural".  I can switch to Ivory Snow if it is better than the Tide Pure and Gentle for diapers/baby but it was about 3x the cost so didn't seem worth it. 
 
As well, do I need to prep/prewash the diaper covers (AF)?
 
Thanks!
Summer