I have recently began to transition from 2* play to 3*play any suggestions on what my best team comps could be and what significance is there to what postions you put your toons in.
There’s solid team comp help in Stage 3 here: https://forums.505go.com/discussion/3939
Character positioning on your team only matters if their match damage values for a specific tile color are exactly the same. This typically occurs only for characters of the same level who share a color with exactly the same match damage (since there are invisible decimal points in the match-damage values in most other cases). For example, Patch & Hulk both have 
as their strongest color and 
as their second-strongest. If both are at the same level, their
&
match damage will exactly match each other. In this case, the order for color-tanking goes Center, Left, Right on the character select screen This means that if Patch and Hulk on your team, Patch is in the center, and there are no stronger green/red characters, Patch will take all green & red matches. Conversely, if Hulk is on the left and the Patch is on the right, Hulk will take green + red matches over Patch.
Thanks for the help.
Even more germane is the team comp guide here:
https://forums.505go.com/discussion/17105
Both yogi_ and I post long lists of team comps (mine is further down the page).