You can put your website behind an “Under Construction” wall and ask search engines not to index it while you’re getting it ready, Bob. You’ll still be able to log in and see the site as it will be when you drop the wall. Be sure to allow indexing as soon as content is ready.
For your autoresponder, each has its own particulars… but you can fill out your own opt-in forms and test each part of the system with them all. Ask support for instructions.