Two different questions....
Your first about sending to many people without them knowing who else is copied is to use the blind carbon copy function in your email application.
Most applications will present you with a TO and CC box, but will have the option to give you a BCC (blind carbon copy) box. When using BCC everyone receives it but their names are not shown on the distribution list.
Whilst this is useful be careful when using it as those people can hit reply all and that reply will go to all on the published list - this has caught endless people out when someone "apparently" not on the distribution list replies with their comment.
On your second request.............
By default this cannot be done (sort of) - the mail protocols in use do not support delayed delivery - you may find some applications may offer this facility but it will be reliant on that application being run 24/7 to send out the required email on schedule as required. All mail servers I have encountered will mark the mail with the time of receipt - so the only way to falsefy that time is to program the source to send at the appropriate time.