In what sense would you argue that he was a Kantian? He was surely influenced by Kant.
Rawls was a Kantian in the sense that he posited that one has to attempt a transcendental apprehension of grounds for supplying the ethical imperative. Rawls differed, then, in how he substantiated the premise by which to apprehend the imperative for social agreement. (See Joseph Grcic (2007)).
However, if all we want to say with Jan Niklas Rolf (2016) is that both Rawls and Hobbes were social contractarians, then I'd agree with your basic premise that Rawls "folds back into" Hobbes. But being that Rawls formed his Original Position via Kantian terms, then I think his metaethical and ontological reasoning differs.
Regardless, I'm not a fan of either philosopher, so...............before getting too deep here in time wasting mud with these two particular ethicists, I'll just say I'd rather apply more complex and extensive study to Ethics and look further afield than upon what either Hobbes or Rawls can provide. This is one reason I mentioned
R.M. Hare in my previous post. I rather like his little book,
Sorting Out Ethics, where he posits that ethics can take on shades of an amalgamation of both utilitarianism and deontology, as odd that that may sound.
Then too, as I consider R.M. Hare's taxonomic form of ethical analysis, I also jump on over and do a dance with Carol Gilligan and use her ethical thought as an additional modernized ethical component by which to frame and express my already heavy investment with Jesus' (and Peter and Paul') moral teachings.
But Hobbes and Rawls I leave to the side. To me, modern social contracts are just a cheap excuse to try to prompt and convince ourselves (or others) "to do" what we so often try to
excuse ourselves from having to do (i.e. all that which Jesus would want us to do for others.)
References
Grcic, Joseph. "Hobbes and Rawls on political power." (2007).
Hare, R. M. "Sorting out ethics." (1997).
Rolf, Jan Niklas. "The fool and the franchiser: formal justice in the political theories of Hobbes and Rawls." Ethics & Global Politics 9, no. 1 (2016): 30042.