I wish I knew the answer to your first question. When trying to get Amazon Alexa online, it said to do so via the app. I have te app on y iphone 6s Plus & also tried online but still no joy.
On the other hand, Echo Dot was online easy.
Originally when visiting my friend, one of us would simply ask her to play music & she did. I now realize he had a paid acct., I don't.
On the echo dot I have to push the button to ask anything thing, I've tried following the hands off settings but it still don't work.
No Android use, just apple. I've used both computer & app settings, no joy.