Bintelli

The 150 in the Bolt is top mounted, where as the Beasts is bottom mounted. 
Not to say it's impossible, but it'd require manufacturing a custom mount. 

There is a rare bottom mounted 150 variant of that engine, but, it's a needle in a haystack to find. 

You could have someone take the engine case, and bore it out to let you fit a 100cc cylinder into it, but that's a lot of work. 

There's a lot of things you could do to get more power, but it's all centered around how much time and money you're willing to put into it, and if you're not just better off trading it for one with a better base engine. 

Same issue.

You have to custom manufacture a mount for the new engine. So unless you're good at welding, it's not going to happen. To top it off, for the amount of money you'd be spending to buy 150cc gy6, and the money and time you'd spend on modifying the Scorch- you could've sold the 50cc scorch, and bought a 150cc scorch. 

This is why I got one of their Adly 50cc 2 strokes. The engine platform it uses can end up making more power then even a fully kitted GY6 150. I went with the bike that had what I wanted to begin with, because custom engine swaps are a pain.