tecnologiaterabyte As for reference, you might want to look at Davis Custom Footer
Please reach out to the author if it is still functional or compatible with the latest Flarum version.
Keep in mind, because of the plan of adding infinite scroolling in the future - footer won't be possible to reach, obviously.
What you are proposing will be perfectly implemented if you are going to use Flarum as a sub-domain for your main website.
(e.g. WordPress + Flarum).
Or, if you are looking for a complicated option - You can create your own custom homepage that has a footer for your Flarum website - Which i won't suggest or prefer not to go that route not unless you have the ability to create one - But if you have $$$, then you can hire someone to work on it and maintain it 😁