Tattooguy, congratulations on a terrific Army Career. The promotion rates, as you know, are tough. Timing is everything in the airlines, so if there is a program to get you in the door now, I'd take the retirement and run vice missing out on a good opportunity for us Army Aviators. There is no guarantee the Envoy program will be around next year or in five years.
There are some recent posts on APTAP about the Envoy program, and it even looks like they will be hosting a recruiting event at Rucker (Dothan) soon.
As far as the contract flying goes, Columbia and AAR would provide you with the financial means and time off to pursue your FW ratings on your own. Also, $100K (I heard it is $108K this year) isn't tax free unless you spend 330+ days overseas or have your primary residence overseas. IRS.gov spells it out quite clear. One day short and you pay tax (State and Federal) on all of it. Guys do get caught skirting the rules and have to pay all back-taxes plus significant penalties. You will max out your social security tax, but the higher pay puts you in a significantly higher tax bracket.
Good Luck.
Above the Best!