You can use your own templates, logos, images, etc. when creating your campaigns for branding purposes. We also have an additional premium feature that removes our logo 'Powered by SimplyCast' from the footer of your campaigns.
Remove Logo is a feature of the professional package. In order to remove it from any of your channels, you'll have to get the professional package in that channel.
You sure can! Just open up your Subscription page by clicking the gear symbol in the upper right of the app, and clicking "Subscription" and you'll be able to change or upgrade your plan as necessary.