I think something may be off with connection today. Even my duels with Shea were laggier than usual.>.>
Anyways for the pika chaingrab, just press the grab button during the last few frames of the D-throw. I wouldn't worry too much about trying to do it online, though. It's way too hard and will screw up your timing offline. So just practice it offline.
Full hop tbolt > grab is all a matter of spacing and punishing your opponent.Similar to Mario's fire ball. Approach the opponent with a full hop and a quick tbolt. Then run and grab your opponent's shield.Be wary, though. A lot of chars like Wolf and Marth have aerials that can cancel your tbolts. Also there are more appl;ications than combing into a grab, such as Full hope tbolt > QAC > pretty much anything,