This appears to be the main discussion area for both cards, so I'll post here.
Firstly, fix your table.
Provided you have enough Entropy quanta, Hyde can remain out on the field for an extended period of time during the attack phase.
^Should be in notes.
Statwise, Jekyll is balanced, and I think the switching forms thing could be calculated in a dive-like manner.
2
for + 7 Atk
So 1
per + 3.5 Atk.
At first, I thought this part might be OP, but then I compared it to Graboid and Shrieker, I found that this card is balanced, possibly slightly UP as you must pay quanta in order to maintain the high attack.
EDIT: You should've kept the health at 4 / 5, for jekyll, now it's rather easy to destroy with a well timed thunderstorm/RoF. If Graboid can have burrow, this card should at least have 3 / 4 health.