FreeBSD for a high school class? (long)

[Chris]

Sorry for the OT-ness of this. I only work with FreeBSD for servers.
Have used it as the sole systems for a business since the late 1900s.
Twice I've put up X-Windows machines but we never bothered to
use them for one reason or another. Now my son's school is short
computers for a High School HTML class I'm going to help teach
this fall. The official teacher is excited about FreeBSD since we can
use old equipment that is donated.

There are two issues. We will not get enough FreeBSD systems up
to cover all kids in the class. Some will have to use the 10.4/3 OS-X
G3s we already have. For the remainder of systems, I've told them
I need a minimum 256GB Ram, 500+Mhz, ~10GB hard drive. I will
put Apache on both types of boxes so they have a testing platform,
hope to put firefox on each so they have a consistent browser. The
confusing thing will be Finder and Textedit, versus whatever I use for
a window manager on the FreeBSD systems.

The two questions are:

1. Taking the specs into account, what is the window manager that
will provide the closest match to the Apple desktop for mouse ops,
browsing files/directories, and editing text files. I suppose I should
add running Firefox (or a reasonable similar browser that will
render HTML and execute Javascript identically).

I don't mean cosmetically, just enough that there isn't too much
needing to teach a window manager. Finder is relatively invisible
from a teaching standpoint as is Textedit, Firefox is going to be
reasonably standard (this is going to teach HTML standards, not
how to use windowed drag and drop page generation products,
they will be using a text editor and working with raw HTML, CSS
and JavaScript). But what I don't want to be doing is having some
learning vi (even though if this were an advanced class, that is
precisely what I'd expect ;-)), while others are using textedit.
The course is HTML. Mouse button operations should be close,
a window that gives a simple file directory and a text editor that
doesn't require learning a character command set would be the
target.

2. Am I too lean on the specs for the free AMD/Intel boxes we
are requesting parents cough up?

The district sadly is being forced to go to windows by the
state, and now only has these old antique Macs
free and has no Intel/AMD boxes. These will all come from
parents of the program and leverage the fact that people
like to replace perfectly good boxes because of spyware on
windows. I personally still have boxes with less than 100GB
RAM and sub-500 mhz processors running 6.x (and I think 7.0)
but I use those as firewalls, I've never used a window manager
so perhaps my view of FreeBSDs efficiency is optimistic. Are
the specs too low for *some* X environment?

Constraint: I already broached the subject of putting FreeBSD
on the G3s using the PowerPC version. Unfortunately, the 6
Apples are used by another class on OS-X.