Ugh, sadly no. I just cashed in before Super Strikes were announced for the 777 Gohan. So I'm sitting at like... 5 gems or something odd. And IIRC he's 300, that'd take me a few days, and by then it's WT time.
I could probably do it if needed, but I'm hoping to find another way -_-
He's not mandatory, just makes it a little bit easier. You'll just probably need to use more items without him.
For King Cold you can afford one empty space for a saibaman, so if the Cost is too much you can remove one of the characters (that's what I did). I've had success with friend Gogeta, leader SSR Tao, SR Bulma, SR Dabura plus SSR Launch and SSR Krillin that you don't have, but you can probably grab Buutenks, Granpa Gohan, Turles or people with stun or attack/defense down in their place.