New Prius owner - Ideas on sounds(not knocking sounds)

Hey everyone! New to the forum, however long time lurker. I'm an avid hypermiler who used to run in a 2002 Honda Civic manual transmission. Average MPG on that car(City/Highway mix - located in Seattle so highway not always highway speeds) was 42MPG with maximum of 58mpg since running with an Ultragauge.

The time came when the constant repairs on the civic was getting to me and I was ready to switch to something that can push my hypermiling skills to the max. Convinced the GF to allow me to sell our beloved Civic and get something a bit "nicer", especially since we have stable jobs(shes a nurse, i'm a software test engineer).

Well long story short, after renting a 2015 Prius over the weekend for our minication, I was sold on it. Averaged(according to the internal MPG) 55mpg over 780 miles of driving(driving highway down to the oregon coast and back).

Well just yesterday we made a purchase on a 2012 Prius II with 53k miles on it. We are now proud owners of the Prius family! I love the vehicle and am tuning the ultra gauge to the car! In the last 50 miles i've driven, I've achieved 51mpg!

Anyways now that we are owners of it, I am hearing some noises that I'd like to get clarified as to what they are.

The first one is when i start up the car and shift from P into D or R there is a "click" sound. This seems to occur everytime shifting and i'm not sure if its "normal". I hadn't noticed it until I had the windows down and music off. I'm not sure if its common to hear but I dont recall hearing it on the rental(though i believe music and windows were up every time i started it). It does occur with the engine running AND without it running, so its not the engine, but more like the shifting?

The other sound that baffles me(again dont recall rental having it), is when i start up the car cold(i think its only when cold), I will hear a sort of chime, more like a spaceship "wommmmmm" sound. Its hard to describe, but I would say it lasts 3 seconds or so. It doesn't seem to happen when the engine starts. The first time I heard it, it was after i had shifted into gear and was backing out via electric only. The second time I heard it was when the engine was running as I was sitting idle in the driveway.

When we bought the car, I had a mechanic run an inspection on the car. He said the only thing is the oil pressure sending sensor had a very small leak which should be addressed within the next 6 months or the next oil change(2000 miles away).

I will try to get an audio capture when I get off work today and share the video/audio file with everyone. I'm more curious to know what is causing the sounds in case something needs to be address priror to major failure(firm believer in preventative maintenance than crucial maintenance).

Thanks all - looking forward to being apart of the forum