Lancet should be easy enough.
Tackle, well... The damage calculations would definitely be easy enough. The visuals (I'm thinking tackle visuals) would require some research and some... Jiggering. It would be a project I'd enjoy working on, but I can't divide my romhacking attention at this very moment. When I finally finish this Chocobo racing thing I'm working on,that would probably be a good time for me to take a break from my own hack to, uh, tackle this one.
I'm thinking that studying the visuals from Kick and Jump (or more appropriately, "Land") would be a good start.
As far as the ability's effect... Personally, I don't think I'd ever use it the way you're envisioning it. I tend to avoid "explode" blue magics like the plague. Typically, allowing a character to die isn't worth an attack that deals damage equal to their HP, because then you take the attacker out of the picture and you have to spend (if you're lucky) at least one round of another character's turns (if you have Life2) getting things back to normal. Typically, if you're resorting to an attack like this, you need that healer to focus on other tasks for the party's survival. The only situation in which this isn't true is when the attack actually ends the battle, in which case the one who ended the battle doesn't get to reap the benefits.
A suggestion: make the attack deal damage to user and target equal to the user's HP minus one. That way, at least Cid can spend his own turns healing himself (or he can continue to attack while the party's healer heals him). You could maybe couple this with a decreased accuracy if you'd like, or a longer charge time, or even a longer recovery time (amount of time until Cid's next turn - which I don't think has ever been done, but I don't see why it couldn't be).
