Blessings

I said Hamotzi on a bagel, and after taking a bite, put on cream cheese and lox. A friend corrected me, claiming that Halacha requires that the first bite should be done when it is in its optimal form, so that after the beracha, one should cut open the bagel, put on the toppings, and then eat. Could that be?

It is unclear to me whether one is supposed to say “Baruch hu u’varuch shemo” at the end of zimun and if so, who is supposed to recite it. What is proper?

May I be mekadeish levanah now, although I am indoors, and I am also obviously looking at the moon through a window? The brocha of borei me’orei ha’eish on an electric light - could one do this when a lightbulb must be encased in glass for it to burn? What do the above questions have to do with this week’s parsha?

Last week clouds covered the moon after some of us began Kiddush Levana. Can the remainder rely on their “testimony” to join the beracha?