Complex Question: Potential Loss of Profile Win 7 to 10 Clean Install

If this is not the appropriate place to post this question, please forgive me and tell me where else it might be better suited.

I have two PCs for which I prepared a Win 7 image using Sysprep to move the users folder to another physical drive.

At the time, my Win 7 OS was placed on an SSD which I had partitioned into C: for the OS and D: for virtual machines.

So, it was for this reason that my data drive, a HDD, with the users folder would be volume label E:

I would separately back up the SSD and the HDD using Acronis.....so far so good.

On several occasions I had to restore the OS....no problem.

Not using the virtual machines, I decided (foolish me,) to delete the D: partition on the SSD.

When my wife's PC had problems I tried to do a restore of the OS only to find no matter how I reassigned the letters using diskpart in the Win PE environment.....I could not get into windows because the user profile was lost....why? ....because Windows decided that it was really pissed off at me for deleting the D: partition and no matter how I tried with diskpart....Windows said....well you get the idea.

However, I figured out what to do....I simply created a small D partition on the SSD and Windows 7 decided to play nice.

As everyone knows, my love affair with Windows 7 must come to an end shortly. I plan to create a new image with Win 10....which brings me to the following question.

I want to get rid of the D: partition on the SSD.

First Question: If I do that and leave the E: data drive as E: will Windows 10 with a clean install and sysprep script for E: find the drive....or
alternatively, can I assign the letter D: to my data drive and when I run Sysprep with a script for D:.....will that work.

Second Question: Somehow, I do not think this will work. I just picked up a Dell Laptop Lattitude....brand new and did a clean install (which was quite a problem.....see other post...,.Dell Latitude Clean Install Problem. It would be nice if I could use the backup image I created for the laptop and try to use universal restore to deploy it to the other PCs....any thoughts (It has only one SSD partitioned to C: OS and D: users?)

I also have windows and programs on C: (128G SSD) and users on D: (HDD).
And also had faced same issue.
When you deleted the D: partition, Windows probably reassigned E: to D:
Drive letters are assigned by the OS. As you changed the drive letters using WinPE, It was only valid for that WinPE.
You should had done under Windows (as it doesn't find the user profile it creates one) renaming the users partition to E:

Win 10 cant use the profiles (E:/users) created by win 7, but you can do an "upgrade" from win 7 to win 10 and it will modify and keep the profiles on E:/users
Or
you can do a Win 10 Clean install (deleting ALL partitions on the SSD) and once you enter audit mode, launch disk manager and make sure the HDD is D: and then, under Explorer rename D:\Users as D:\Users_old, then run sysprep to create a win 10 D:\users.
Once you finish Win 10 installation, move your data from D:\Users_old\Name to D:\Users\Name

I don't like Win 10 as much I like Win 7 (that is still my main OS). Nothing will change after M$ end of support. Win 7 will work the same way it does today for many years.

I did not understand you Second Question. Could you please explain in more details?