exeng - those are questions you might get/see answered on the Blynk Community board - or by email to the folks at Blynk - I clicked the EMAIL on my phone and got a prompt response - if only to my KS question.
Looking at your example exeng I was HAPPY to see the usability of BLYNK - thanks for showing it work in advance of the official support - thinking it might offer advantages over Particle (or with Particle), then I was SAD when I saw the ENERGY demands - then I was HAPPY I bought the BLYNK Widgets in the OAK KickStarter.
I could go create a project and try adding widgets - but my observed behavior might be influenced by my 'account type', and I have not done that yet - so I can't say if there is a single charge for the project - or for each added widget - or what widgets are usable.
Your existing projects should keep working - just don't recycle them! I don't know what you'll see on changing them. I suspect they will be updating their policy as best they can to accommodate the (-) feedback they are getting.
I know I created a SECOND account - it got 2,000 ENERGY to start - and I could not use my KS QR a second time - so the QR code is one time coded. If you create a second account - you might try a project there and see how far you get adding widgets and see if they take ENERGY, without harming your main account and existing work as their policy changes play out.
<edit>:
Confirmed - I am charged 100 to 900 ENERGY to add each widget to my project (0 for Twitter). The problem [noted on the Community] is you are charged to add it - even if you then find you want to remove it during development. This seems like the thing that 'should' be changed - if you add and never use a widget because (wrong type or whatever) - but that is a discussion for the Blynk Community to discuss/resolve.
Another question relates 'LINKED' projects - that costs 1,000 units to share - it can be viewed and used but not edited - I assumed there is no ENERGY cost to the viewer of the linked Project. So I can't create a project (to my hardware) and share it with a post here - I'd have to do it through the APP. I assume I could let others CLONE it for their own use - but then they'd have to put ENERGY into it I'd suppose to activate all the elements with nothing free of ENERGY cost somewhere. Again more for the Blynk Community ...