Most people think of copyright as a criminal issue, and some of it is but it is primarily a civil issue. Law is mostly based on the past (precedent) rather than the future (changing technology and social acceptance, common use etc.) and unfortunately law is woefully behind the times in this area.

So I believe that your answer is to not worry so much about including too many avatars installed in the distribution package but making avatars that are in common use available, and letting the individual Admins decide which to include or exclude in their Forums.

For my purposes I use a few standard sets which are and have been in common use for years, some of these have been distributed "as in common use, and (are) believed to be in the public domain" for years now and I am quite comfortable with that.

I do this as a hobby and as a public service as a private citizen, I do have a legal name I function under which is barely Germaine to the subject, but the point is that if I have my way I will have a hundred free forums on line (tailored to different tastes and subjects) by the end of this year through the U.S.A. 2016 election cycle.

And if I can accomplish it, registering on one will effectively register the user on all or at least many of the others, thus allowing the user to use one avatar and user name across the board rather than dozens of different individual registrations (refer to the virtual forum concept included with 2.8.1) and that is by any stretch of the imagination a public good which any lawyer would avoid like the plague.

And I do not see that FUDforum is all that different, it is obvious that Prohost is not in it just for the money (I have asked about a service contract several times without response), there are no advertisements beyond the services link, and a single pay pal donate button above. So FUDforum is clearly a loosely coordinated group of individuals with a common interest in helping each other develop a superior software platform for the common good. And in all the reading I have done here I can recall only one instance where any one even suggested donating money to the cause.

So if you all are really interested in Avatars I will add about 1000 of them (300 or so different ones in 3 different sizes) to needful things and the users, contributors, developers, an administrators can use them as a "standard as they wish" .

These are all to the best of my knowledge in the public domain, they are all in common use (on a wide variety of platforms public, private, and commercial, forums, Blogs etc.), they are all readily available from a variety of sources, to my knowledge no one claims ownership rights to the avatars themselves (although some one clearly has some claim to the ownership rights to the original art work they were derived from), to the best of my recollection these have been in common use as avatars for at least 8-9 years and the images are older than that 15-30 would be my S.W.A.G. so I believe ample precedent has been set to consider them as being in the public domain and subject to fair and open use by the general public.