@JDRoberts I didn’t think the Echo could be used for announcements, only in response to a question directly asked to the Echo skill…
@why hy You can still use a tablet or a computer running VLC (Tablet options have been covered above and VLC can be done via a VLCThing device type handler).
In terms of how to do different things… then please do use the search 
In terms of a notification if you leave windows open then the below app I believe does this (after an easy search):
Or Big Talker:
For vacation lighting:
Alternatively CoRE or webCoRE allow you to build your own fully customised rules for pretty much anything!
Personally however I’m using an app I’ve written myself which handles all my lighting, security, notifications, scenes etc etc which does both of the above you have asked for and in fact a lot of other things… it’s searchable under SmarterHome but support is limited as I am the only developer and as far as I am aware the only user (I haven’t intended for it to be a mass used app as I don’t have the time to support it) The app however is incredibly powerful and customisable and built to make all things play nice together, rather than a bunch of independent apps…