On the Wiktionary definition of nonspecific, it notes:
Synonyms
unspecific (less common), inspecific (much less common)
The entry for inspecific does include quotations.
Google n-grams shows for nonspecific,unspecific,inspecific that the ratios between them is approximately 1000:100:1 respectively, i.e. for every 1000 uses of the word nonspecific, there is only 1 use of inspecific. This makes it almost unheard of by most people.
As an example, my browser's spellchecker says inspecific is misspelt. So you can use inspecific, but you need to expect that you will be continuously challenged about it. You can avoid being challenged every time by using nonspecific instead, as it is the most common of the three words.
Here's an Ngram chart that tracks the frequency in Google Books search results of "wrought havoc" (blue line) versus "wreaked havoc" versus "worked havoc" (green line) for the period 1800–2005:
Although "worked havoc" has, since the late 1800s, been consistently less common than "wrought havoc," both show the same hill-like trajectory, rising between 1880 and and 1920, peaking between 1920 and 1940, and declining between 1940 and 2000. This shared behavior strongly suggests that people who used "wrought havoc" understood it in the same sense that they understood "worked havoc"—as meaning "to create or produce or effect."
In contrast, the sense of wreaked in the phrase "wreaked havoc" is a rather late addition to the dictionary-approved definitions of that word. Here is the entry for wreak in Merriam-Webster's Eleventh Collegiate Dictionary (2003):
wreak vt (bef. 12c) 1 a archaic : AVENGE b : to cause the infliction of (vengeance or punishment) 2 : to give free play or course to (malevolent feeling) 3 : BRING ABOUT, CAUSE {wreak havoc}
The crucial definition 3 is rather odd in that it presents wreak as an objectively neutral synonym for "bring about" or "cause" despite (1) being posed in the company of havoc in the example usage, (2) having as its only other current meanings the inflicting of vengeance or punishment and the giving of free rein to malevolent feeling, and (3) strongly suggesting to the unschooled ear a connection to the (objectively unrelated) verb wreck.
As recently as the Fourth Collegiate (1931), wreak had only one listed definition:
wreak v. t. To execute in vengeance or passion; inflict.
The Fifth Collegiate (1936) revamps its entry for wreak, producing something akin to the Eleventh Collegiate's first two non-archaic definitions, but with no hint of the crucial third definition there:
wreak v. t. 1. To give free play or free course to (wrath); as, to wreak one's resentment on the innocent. 2. To inflict or exact (vengeance); as to wreak vengeance on an enemy.
The third definition doesn't arrive until the Seventh Collegiate (1963), and it appears in a form that still suggests something dangerous about the "bringing about" that wreaking implies:
3 : CAUSE, INFLICT
Finally, the Eighth Collegiate (1973) adopts the neutral language that all subsequent editions have retained:
3 : to bring about : CAUSE {wreak havoc}
As you can see in the Ngram chart, the period 1960–2000 is the period of steep growth in Google Books matches for "wreaked havoc." It appears that either Merriam-Webster recognized this trend early in its development or actively promoted it (or both).
In any case, I can't see how the skyrocketing usage of "wreaked havoc" in its sense of "caused or brought about havoc" in any way undermines prior and contemporaneous use of "wrought havoc." It also seems clear that, during the heyday of "wrought havoc" and "worked havoc," "wreaked havoc" was not widely used as an alternative to those formulations, which makes the idea that "wrought havoc" was somehow an erroneous rendering of "wreaked havoc" extremely implausible.
As a final note, I want to point out that the most widely used expression for "bring about havoc" during most of the period 1800–2005 was "played havoc" (the yellow line in this version of the Ngram chart):
The rise and fall of "played havoc" very nearly mirrors the corresponding up and down of "wrought havoc" and "worked havoc." The circumstantial evidence is thus very strong that "wreaked havoc" made its gains at the expense of the other three phrases tracked in this Ngram chart.
Best Answer
Using "and" more than once in the same list sounds awkward. Use the commas.
That's not to say that you can't use "and" more than once in the same sentence, as long as it's joining different "kinds of things". Like, "I gave the green box to Bob and Sally, the red box to Fred, and the yellow box to Janet." I use "and" to join Bob with Sally and also to join what I did with the three boxes, but it's in different contexts, so that's okay.