How best to manage Perpetual liscence for a small chairty

So, after a frustrating 40 minutes on the Adobe chat, where I explained this scenario below and was pushed into a sales call, two salespeople tried to encourage a solution of a subscription model. They then said they did not know very much about the perpetual licenses and gave some generic advice prefaced with, “From what I know…”  So..... I am reaching out to see if anyone in the community can help.

its funny people refer to these as "perpetual", when actually they only last 3 years. But that is what the help staff referred to them as.

Background:

We are a small charity with 6–8 staff members and normally 2 interns.

We own around 18 perpetual licenses for the following:

Adobe Premiere Elements

Adobe Photoshop Elements

Adobe Acrobat Pro

The interns change every year, and quite often, we have staff changes.

We cycle machines into the organization, with the staff who have the heaviest needs getting the newest machines, while the older machines cycle down. Staff generally never stay on a single machine for more than 2 years, and we could have new staff/interns every year.

Question

Elements software generally lasts for 3 years, so each year we purchase 2–3 more licenses. However, how is it best to manage these licenses, especially were staff can change?

Let me give a specific scenario:

Bob joins the charity as an intern for one year.

All our interns do some photo editing and videos for social media, so we (the charity) buy and install Premiere Elements and Photoshop Elements. Bob does not own the software - bob is just a user.

During the installation, Bob gets an organization email, bob@charity.org, and sets up an account with Adobe. Bob logs into Premiere Elements and Photoshop Elements with his email.

Bob, after one year, leaves the organization when his internship ends. Bob’s machine is fully cleared, his email is removed, and the machine is set up with a new install for the next intern and a new email.

The new intern, Jill, joins and takes over from Bob. Like Bob,  Jill will also do some photo editing and videos for social media.

The charity already owns Premiere Elements and Photoshop Elements. Bob has left the organization, so he is no longer a user of this software. We now want Jill to be the user of this software.

Currently, the software is still showing on Bob’s online account.

How best do we manage these situations?

1. Can we fully deactivate the software from Bob’s machine (before clearing it) and deregister it from his account to leave it open for Jill? (I only see an option to sign out - do this deregister?)

2. Can the Serial number on Bob's account be registered to Jills new adobe account or,  are we better off giving Jill Bob’s old Adobe account (i.e., doing an email change)?

Note we can set up staff in old roles to forward email to the new staff.... Ie all bob's emails  will now go to Jill.

3. Are we better off creating one Adobe account (e.g., staff@charity.org) and using this for all software bought by the organization? This way one account can manage everything.

Is there problems with any of these ways or is there a better solution. 

We had a situation in the past where we lost access to software from a staff member that had left two years earlier and we had to recreate a new email for him, to get back into his account. 

So any helpful suggestions. 

Subcription based options are not in our budget. looking for solutions specifically for the mentioned types of software. 

Many thanks

Scott