G Suite for education is supposed to be FERPA compliant so as long as the business side uses the same level of protection, it should be good.
We are an Office 365 campus and there should be similar programs to Google Education. I don’t personally handle that part of the system, but one of the managers was talking to me a few months ago and told me that Google is free for students and paid for faculty/staff. He also said the Office 365 was very similar where students are free (or included in the plan) and faculty/staff are the paid part. I might have some of that wrong, so I would advise speaking to educational sales at both Google and Microsoft. You may also be able to go through a partner like HP or Dell for both of these conversations.
Also faculty are “encouraged” to use the Microsoft products for all classroom activities due to FERPA compliance. Doesn’t stop them from using personal Zoom accounts or other personal accounts for things. No one is willing to force the policy and only exceptions for those things that do not work on the MS products or have another FERPA compliant method like our tutoring system.
As far as PII over email, parents should be encrypting those messages, kind of a hassle with Outlook, but the option exists, I’m sure Google has a similar method to encrypt emails. Another option would be to make a secure web form for PII input and keep that on the FERPA compliant systems (onprem or cloud).