Hyperbundle as a newish Player with few over 5 stars toons ?

I read that, just for the materials and all the other stuff, It is worth but will I get something extra for those Characters that are maxed or near max out ? Or with those Max Characters / Over 5 Stars, I would "lose" the paid upgrade ? 

I know is not that many but still leaves a bad taste when I'm paying for the Bundle and I get nothing for those toons. I read somewhere also that sometimes the Bundle is 50% off ? Is it true ? 

Does the bundle have a 4th May discount or it's just random ?