Usage of "well-intended" vs. "well-intentioned"

To put together a data-based, descriptive (rather than prescriptive) answer to this question, I looked at two blocks of Google Books matches for "well intended" versus "well intentioned": one for the period 1803–1817, and the other for the period 1998–2008.

Google Books results for 'well-intentioned' and 'well-intended' in 1803–1817

The 1803–1817 block for "well intentioned" turns up the phrases "well-intentioned subjects [of the king]" (1810), "well-intentioned Prince" (1814), "well-intentioned men" (1817); but also "well-intentioned advice" (1803), "well-intentioned visit" (1810),"well-intentioned purpose" (and "well-intentioned suggestion," from the same 1817 book).

The 1803–1817 block for "well intended" yields matches for "well intended Tract" (1811), "well-intended Assistant" (namely, The Tutor's Assistant, a book, 1811), "well-intended object" (1811), "well-intended purpose" (1811), "well intended designs" (1812), "well-intended services" (1812), "well-intended offices" (1812), "well-intended combinations" (1812), "well-intended bequests" (1813), "well-intended raillery" (1813), "well intended blow" (1813), "well intended enterprise" (1813), "well intended deed" (1814), "well intended line" (1814), "well-intended kindness" (1815), "well-intended advice" (1815), "well intended chastisements" (1815), "well-intended presents" (1815), "well-intended aim" (1815), "well intended bill" (1815), "well-intended charities" (1815), "well-intended labours" (1816), "well-intended exertion" (1816), and "well-intended project" (1816).

The results for this period thus show an even split (three and three) between animate and inanimate things in the application of "well-intentioned," but a complete dedication (twenty-four out of twenty-four) to inanimate things in the application of "well-intended." These outcomes do not suggest that "well-intentioned" was understood in the early 1800s to refer only to animate things, but they do suggest that "well-intended" was understood to apply only to inanimate things.

Google Books results for 'well-intentioned' and 'well-intended' in 1998–2008

The 1998–2008 block for "well intentioned" produces instances of the phrases "well-intentioned racist" (1998), "well-intentioned supporter" (2001), "well-intentioned Machiavellians" (2005), "well-intentioned youth worker" (2005), "well-intentioned ruler" (2005), "well-intentioned parents" (2005), "well-intentioned spiritual brethren" (2005), "well-intentioned respondent" (2006), "well-intentioned reformers" (2006), "well-intentioned revolutionaries" (2006), "well-intentioned visitors" (2006), "well-intentioned persons" (2007), "well-intentioned people" (2008), "well-intentioned institutions" (referring to the people within them who "know how to get money made," 2008), and "well-intentioned scientists" (2008); but also "well-intentioned touch" (1998), "well-intentioned policy" (1999), "well-intentioned approach" (1999), "well-intentioned actions" (2002), "well-intentioned feedback" (2005), "well-intentioned attempts" (2005), "well-intentioned gift" (2006), "well-intentioned response" (2007), and "well-intentioned merger" (2008). In addition, one book from 2006 uses the phrase with both animate "well-intentioned ones [that is, people]" and inanimate (well-intentioned protection") things. Another book from 2007 does the same thing, with "well-intentioned but ignorant policies," "well-intentioned ideas," and a "well-intentioned organization" (meaning the people in it). The example that calls policies "ignorant" is interesting because that adjective, too, is often thought of as an attribute of animate things.

The 1998–2008 block for "well intended" gives us "well-intended prescription" (2000), "well-intended philosophy" (2001), "well-intended projects" (2001), "well-intended parental caring" (2001), "well-intended halfness" (2002), "well-intended ideas" (2002), "well-intended Bill C-68" (2002), "well-intended policy" (2002), "well-intended laws" (2002), "well-intended displays" (and later "well-intended conduct," 2004), "well-intended actions" (2006), "well-intended attempt" (2006), "well-intended research design" (2006), "well-intended regulations" (2008); but also "well-intended people" (1998). Although the one person-oriented instance of "well-intended" looks like a freak occurrence in this set, I noticed several similar instances where "well-intended" was attached to animate things in results from the 1970s, 1980s, and earlier 1990s.

The results for the recent block of Google Books matches work out to seventeen animate and eleven inanimate objects connected to "well-intentioned," and one animate and fourteen inanimate objects connected to "well-intended." These results indicate that many writers (and their editors) probably make the same distinction between "well-intentioned" for animate things and "well-intended" for inanimate things that the OP does. Still, it seems clear that "well-intentioned" has always (since 1803, anyway) been applied to a significant degree to both animate and inanimate things, while the preference for limiting "well-intended" to inanimate things has always been quite strong.

Relative frequency of the two terms in Google Books results, 1803–2008

Also worth pointing out is the change in relative frequency of the two adjectives over the 205 years from 1803 to 2008. An Ngram chart of "well intentioned" (blue line) versus "well intended" (red line) shows a significant trend in favor of "well intentioned" during that time period:

In this regard, I note that the Ngram graph cited in vahokie02's answer is quite misleading because it tracks not "well intentioned" versus "well intended" but "well - intentioned" versus "well - intended" (where the hyphens may be functioning as minus signs). Whatever those hyphens may be doing, Ngram cannot handle hyphenated words in a consistent and reliable way. A further sign that it is struggling with the search terms in vahokie02's graph is that it doesn't provide any searchable matches beneath the graph; in contrast, the Ngram graph that my Ngram chart above is based on provides two rows of searchable results, one for each search term. I have found that an Ngram search that omits hyphens from what would normally be hyphenated search terms nevertheless returns results that include both hyphenated and open versions of the search terms.

I think well-intended is a non-standard (or at least less common) synonym of well-intentioned (Google's ngram shows well-intentioned as about six times more likely). Googling for the definition of well-intended shows simply well-intentioned. Given this, I disagree with your distinction. I would use well-intentioned in both cases you list.