Either my examples are just too tough, everyone is reluctant to cheat due to such a high level of integrity, or (and ALAS this is likely the answer) this just doesn't interest anyone :(

That said, here are some clues/answers to the first unanswered 20...I will eventually learn to let go and let the thread die its natural death. It's just so hard to let go of one's first posted thread <sob> <sob> <sniffle>

3. FBF febrific < febrifuge (dxb)
4. GFM gasiform shorter than engulfment (tsuwm)
5. GJG it sometimes happens on airplanes
6. GMV form of the word argue
7. IMJ jimjams (Slang)
8. IQB (solid, gas, ...) form of the third state of matter
10. KXY alkoxy
11. MZB it has poles.....form of the word
12. OKV not as uncommon a combination as I originally thought when I posted here...outknave, booklover, shockwave, bookshelves, pocketknives
13. SVF having the power to bring redemption
14. TFV putrefactive
15. TZU tzuris
16. WJE swarajes (probably just too obscure a word)
17. XQA exequial (of or relating to funerals)
18. YVC sylvatic (affecting only wild animals)... polyvalence (TED)