the hold package is good, it can help a lot on CS support and live chat prospective.

but for customization, I find that they will soon provide/ remove their logo in the bottom of widget chatbox in Q&A page, sounds good !

but the final one is the widget icon customization. Many live chat/chatbot plugin providers provide flexibility for a paid plan to use our own icon/image in the floating button. And I have asked Replain CS the same questions. in this stage, if we need to modify the widget icon, we might to a website developer to do the integration.
and i find their roadmap in https://replain.cc/vote
customize the design of website widget is planned, and their cs say maybe yes, to have a UI to modify your floating button.

Five Taco rate if they can offer a UI to customize the design of website widget in future