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Definetely not easy, they are quite hostile regarding their branding and using system libraries, and to top it off they are basically maintaining old versions of libs themselves. (Personally the OpenBSD port debacle is enough reason for me to never touch that browser again)
As for other browsers running on Haiku, we have some, The big next one beeing netsurf (the haiku frontens could use some work though). And also links2 runs on haiku quite well
Don’t overlook QtWebEngine (i.e. 3dEyes demo). Looked promising.