Competitive research is a critical step before you even start your messaging and positioning exercise — I see it as an input rather than an output.
I have a few favorite messaging frameworks and usually combine my favorite elements into one. Geoffrey Moore's classic FOR...WHO...PROVIDES...UNLIKE...ONLY framework (not sure where this originated) is a solid start for messaging.
For personas, we build cards that cover demographics, sensibilities, responsibilities, pain points, motivations. There's no wrong way to do it but for enablement and internal education, it's best to distill into something easily consumable.