1. No. Civil Subpoena Duces Tecum is not the same as a Deposition Notice (which is only for a "party" to the case, and wouldn't be appropriate for a trial -- it would be a Notice to Appear).
2. Yes. This document must go to the consumer and to opposing counsel/party so that they have sufficient time to move to quash, if that's what they want to do.
3. Yes. And, the notice regarding the notice must be served on the witness so that he/she/it is aware that you have properly notified the consumer.
4. Yes. Have copies of all at trial in case you're challenged, or the witness doesn't show up. Otherwise, you won't be able to continue the trial.
Also, you should try to be as far out in front of trial as possible, because, for example if you are subpoenaing a large corporation, the custodian of records will always try to find a reason to not appear, and if anything is out of order, you will end up with a letter telling you "Sorry, try again."
Finally, it's usually a good idea to send a cover letter to the witness telling them where and when to be at trial and that you can keep the on call if they are willing to appear with 30 minutes notice and provide you with a phone number where they can be reached on the trial date. The idea is to make it as hospitable for a witness as possible -- otherwise you may end up with a hostile witness, which may be worse than no witness at all.
Even if the witness is hostile, it's good to make it seem to them like they're not.