Users often don’t invest enough time into their messages, resulting in incomplete, unprofessional, or otherwise under-whelming greetings. Sure, crafting a greeting doesn’t sound all that complicated; however, there are a number of pitfalls users can fall into—i.e. informality, terseness, sincerity, lack of direction, and more. While none of these sound too catastrophic, they are often interrelated. As such, they tend to worsen any problem. For example, humor can cause informality, worsen ambiguity, and weaken sincerity. That being said, users should strive to avoid ALL these pitfalls.
29. Hi, this is [your name] at [X company]. I am on vacation right now and won’t be back to the office until [X date]! Please leave me your name, phone number, and the reason you are calling, and I will get back to you then. Alternatively, you can phone [Name] at [phone contact information]. Thank you for calling!

Many busy businesses utilize auto attendant greetings to make a great first impression, however, if your business relies on the personal touch of a live receptionist, it is important to have a plan in place when that position is unstaffed. Make sure your voicemail greeting contains the useful information that your receptionist would normally provide. This could include: location & directions, office hours, website URL, or social media info, as well as any pertinent company information.
Re: Voicemail for Auto Attendant & Call queueing. Yes, believe this was covered earlier, or in another thread. Basically need to have a user with UM/Voicemail enabled in your O365 tenant, then the AA routes to a "person". So it will costs you a full E3 license to enable UM/Voicemail.