Hi Martin,
In my case, the 'beholder' are millenials who are daily users of Facebook and Twitter and other web 2.0 sites. Compared to those UX, WDA looks outdated by a million years. 
1. I dont have my notes with me but im sure it's there. Just read through the documentation.
2. Yes, You have to upgrade LSOFE to 607 to get additional functionality offered up to EHP7. I dont know what 617 is for.
3. Technically you can use the BSP app innEHP6/7 but it wouldn't be fair to your customer that youll be using old stuff when theres a 'new' one, isnt it? Best to present the two and let the customer decide. 
cheers
Stephen