Auto fold mirrors are only standard on Premier model, or as part of the Leather seat pack on F-Sports, otherwise it is a manual button switch inside. It appears the autofold mirrors need some components of the memory seat package, so a retro fit maybe expensive.
I was also disappointed that Lexus didn't offer any kind of adaptive headlamps as option or standard on the IS, as my current Vauxhall has this and they are brilliant, quite literally! However, the std Xenons and LED's are very good in the dark I thought, so not so bothered.
The demo cars I had, the Sat Nav voice is on over the top of the music or phone. There is an option in the settings to not have it on over everything, so if you are on a phone call, it is silent. It doesn't turn down the music/radio though so you can hear the satnav better as my Vaux does now which is disappointing, but maybe this will come in an update - the SatNav/Radio system is on release D currently, there are other threads on here about upgrading it if your dealer can't.
Screenwash dilution is to whatever the product says, if the bottle doesn't have a dilution ratio, it probably means it should be used neat.