My websites are actually written for Bootstrap 3 and I use
1000hz.github.io/bootstrap-validator/ - works a treat - but that is whole another story! (I would have mentioned a J-Cook BS3 optional feature - but you have enough work to do
)
When I need to use a J-Cook component page, I use Protostar fluid template for that page and dumb it down so it looks much the same as the sand box. For the general public I usually write my own BS3 module to display the data in the way I like.
Before BS3 came out I just wrote my own simple validators and had all sorts of headaches.
So in short, for me, I don't really know what you should use - just as long as it looks good in Protostar. (Or whatever the sandbox template is).
For Validation, I would suggest to avoid hovering boxes as they usually get in the way of things. Better to write the validation error message in a line below. See how neat bootstrap-validator works. Maybe there is a BS2 version about?
For "Information Messages", perhaps use the HTML title Attribute (
www.w3schools.com/tags/att_global_title.asp ). Hovering boxes for these is OK because they disappear when you move your mouse to input.
Bootstrap does tool tips this way...
www.w3schools.com/bootstrap/bootstrap_tooltip.asp (but that might be BS3)
I'm not a fan of bvalidator for these reasons. It uses hovering boxes for validation - which looks ugly when there are a lot of errors.