Is there a specific kind of lawyer that is best suited for this work?
We run our SaaS on Digital Ocean's backend and their TOS says that anything we allow onto their boxes has to comply, so that means our customers have to comply with DO's TOS.
To handle this, we link to theirs in place of a custom one.
I like this. I imagine it’s roughly similar eg using heroku?
It might be. Worth checking into their TOS to see if your customers must comply. I'd say, "probably."