Is it possible to add the electric sunshade for the back window? I guess anything is possible so I should say practical. Thanks!

Not worth the extra costs. It's a convenience for kids in child seats but really the side windows have more of an impact compared to the rear window anyway so meh!

I remember a thread in here where somebody added the reclining seats and the rear shade and per that bloke, the wiring harnesses needed were already behinid his existing seats - he went to a salvage shop to purchase the required farmes, etc to install it all.
For me, I had my all my windows and windcreen tinted. I had them go 1-step lighter than 'limousine' tint on the sides and rear window and I also had him add the colourless UV film on the inside of the windscreen. The car cools fast and stays cooler in the South Florida sun and the biggest difference comes from the windcreen. On 95 degree direct sunlight days, you can touch the dash and the steering wheel and they never get hot because the windscreen no longer gets hot on the inside surface. The Air Con cools in an instant because the dash vents don'r get heated from the sun. It also removes UV rays to protect from fading and drying out the dash and front seats.
I belive the entire tint for all 6 side windows, the rear window, and the film on the windscreen came to about $250 and although that's not cheap, it's cheaper than a rear shade that does very little to keep the rear cool and does nothing to prevent drying and fading of the rear deck and seats.