Hello there,
I have updated apps from Swift 3 to Swift 4.2 more than once, I would be glad to help you. I have more than 3 years of experience as an iOS developer, I've worked on Objective C and all the versions of Swift.
There are several milestones you mention in your project, one is the conversion of the swift version code, the other is the pod install, which is probably related, you might be using the wrong version of the pods. And also clean and beautify the code.
I can do all of those tasks, regarding the distribution of the app without an apple developer account that can be done without trouble.
When it comes to maintaining code I know how to use GIT, which I think is the best friend of all developers and would be more than happy to make comments on your files, we would need to define just a standard and that would be alright.
I honestly have never used freelancer before so I don't know how the proposal works. You don't specify how big the project is, how many developers have worked on it, if they followed the same standards and patterns or not. What I can tell you is that my bid would be 25 per hour, and I can dedicate to the project 30 hours per week.
Hope you find me suitable for the job and I look forward to hearing from you soon.
Thank you,
Fernanda.