Blastoise SW and Foretress LA

[Shino Bug Master]

I have a few questions on the timing in the actions of these two cards.

http://pokegym.net/gallery/displayimage.php?imageid=31850

http://pokegym.net/gallery/displayimage.php?imageid=35724

So when i announce "Waterlog" do I have to say how many energies I am going to attach?

And when do I flip the coins for Iron Shell? Say I have 3 energy I plan to Waterlog. Do I get to attach them one at a time and flip after each time I attach them, or do I attach them all at once, and then flip for however many I attached?

Finally, Foretress' Iron Shell was errat'd to exclude the "may" in it correct? It is something I must do if I attach a basic energy in the way that would trigger it correct?

 

[PokePop]

You can't jump back and forth, again and again between one action and another.
Waterlog's attachments are all one action.
You attach them all, and then, after you have attached them, you flip for each and every one.

Here is a link to the errata section of the Compendium: http://compendium.pokegym.net/compendium-lvx.html#c3
You will find the errata for Iron Shell there, and it says that it is not optional. You must flip.