I searched through Dragon tonight and compiled more info on Jean's work at TSR:
Dragon #24 (April 1979), "From the Sorcerer's Scroll" by Gary Gygax - Jean Wells is now on the staff of a new Design Department (pg 19).
Dragon #25 (May 1979), "From the Sorcerer's Scroll" by Gary Gygax - the DMG is finished and "TSR's new Design Department, namely Lawrence Schick and Jean Wells, undertook the authorship of two sections - ostensibly to test the mettle of these good folk, but actually to assure that the whole manuscript would be finished in a timely manner" (pg 33).
Dragon #28 (Aug1979), "The Dungeon Masters Guide and a Few Words", capsule reviews of the DMG by various TSR staff that worked on it, including Jean Wells (page 5).
Dragon #31 (Nov 1979), first Sage Advice column, by Jean Wells (pg 26). Runs through column #39 credited to her alone. Gone from issues #40-41, reappears in #42 indicating that it will now be answered by multiple authors. Jean answers a few more questions in issues #43 and #46.
Dragon #34 (Feb 1980) - playtester for Doomkeep module, Second Official AD&D Masters Tournament (page M10).
Dragon #39 (July 1980), "Women want equality and why not?", Jean Wells and Kim Mohan (pg 16-17). Also credited as an artist in this issue, but I couldn't find an illustration she signed.
Jean Wells - TSR Bibliography
Monster Manual (1979) - Interior Art added to Aug 1979 revision (Eye of the Deep, Giant Sumatran Rat, Otyugh (with "Dave"), Violet Fungi)
Dungeon Masters Guide (1979) - Uncredited authorial work (per Gary Gygax in Dragon #25)
Lost Tamaochan (1979) - Interior Art and other help
S2 White Plume Mountain (1979) - Editor
Dragon #28 (Aug 1979) - Capsule review of DMG (pg 5)
Dragon #31 (Nov 1979) - Author, Sage Advice column (also issues #32-39, 43, 46)
Rogues Gallery (1980) - Design, Editing, Layout; includes her character Ceatitle
B2 Keep on the Borderlands (1980) - Co-Editor
Dragon #34 (Feb 1980) - Playtester, Doomkeep module
B3 Palace of the Silver Princess (1981) - Author and Interior Art
Dragon #39 (July 1980) - Co-Author, "Women want equality and why not?" (pg 16). Also has an artist credit for this issue.
A4 In the Dungeons of the Slave Lords (1981) - Interior Art
Polyhedron #3 (Winter 1981) - Interior Art ("Plant Creature" = Jupiter Blood Sucker from B3)
Polyhedron #4 (Jan 1982) - Interior Art (illustration of Duchess and Candella)
Jean Wells - author and illustrator