I have a couple questions about wiring a hot tub.

Question 1) Can I run my ground to an existing 120V ground? Will this ground be able to hold the charge of the larger ground, should they be needed?

Question 2) Can I run my two hot wires to one hot wire in a disconnect box? Will I get the necessary amp draw from the one 240V hot?

Before you say it, I am aware that these hypothetical ideas are against NEC code.

Thanks for any assistance.

1) no. Ground conductor sizing is based on the breaker size.

2) Don't understand your question. A 240 volt circuit requires two independent hot lines. Connect both L1 and L2 conductor to T1 incoming, you'll have zero volts between L1 and L2.

Don't try to do this on the cheap - and don't install without a ground fault circuit breaker.