Posso alterar a aparência da minha página de checkout do PayPal por meio do MemberMouse?

Não. Não há nada no MemberMouse que será feito para alterar a aparência de sua página de destino do PayPal.  

Dito isso, há dois aspectos a serem observados:

1. The PayPal account you have can influence the checkout page used on PayPal. As it’s a PayPal feature, we are not clear on how this works but we can say that older PayPal accounts will use different pages than new ones.

2. PayPal processes one-time payments differently than subscriptions. One-time purchases will go to a checkout page on PayPal that’s significantly different than the one for subscriptions. The reason is that with a subscription, a PayPal account is required; with a one-time purchase, it’s not. You can attempt to purchase a one-time purchase product and see the difference.