I was able to order the beamer and am satisfied with it. We connect the projector with the HDMI cable. The speaker in the projector is usable, but it might be better to use an active speaker. We do this via Bluetooth. Everything works perfectly.

Yes, you can. It does support the mirroring function of you iphone, which works through WLAN. Basically it's Miracast. Works with: iOS, Android, Mac OS, Windows.

You are right. Also, according to "Acer" it's 5000 LED lumen. Thank you very much for bringing this error to our attention. We already forwarded your hint to the responsible department so that the information can be adjusted asap.