1. You should pitch your yeast as soon as you can after the wort is prepared, unless there is good reason, e.g. wort too warm for the yeast. Arguably that is the time it is most vulnerable to nasties when there is no yeast present.Saving the hops that came with the MJ for another brew, i added 25g of Saaz . I usually mix the wort and then leave it about 24hrs in the place that i ferment, just so it acclimatises, then add the Saaz in this case and then pitch the yeast, i then took out the saaz after a week ( it was in a hop bag). I usually leave all of my brews for 14 days in the fv before bottling/kegging.
2. If you dry hop at the beginning of a fermentation a lot of the volatile oils will be stripped out of the beer driven off by CO2. Better a dry hop when the primary has almost finished or later.