Yes, the lens hood is included in the scope of delivery. You only need to remove the decorative ring on the lens to attach the lens hood to the bayonet.
mFt has a cropfactor of 2, so 2x25mm. Why would that be bad if it was 70mm for portraits? That would even be good. 50mm would be too short for portraits, but of course it works.
This is a fantastic lens. better than more expensive lenses. It comes in a very small box with a lens hood, but without a case.The quality of this lens is almost as good as the best lenses ... like the 12-35 or the Leica 15mm. Highly recommended
Of course! simply make the aperture smaller (i.e. higher f-number). But the argument for buying a fixed focal length with a great f 1.7 is usually the beautiful bokeh at a wider aperture.
Yes, this lens works perfectly with the Lumix G81. I use the lens on my Lumix G9 and the image quality and bokeh are really nice. If you decide to go for the lens, I wish you lots of fun and great pictures.