There are tons of issues caused by "not bothering to read William H. Keith's original" here.
The creator of the TFL, WHK, had a different backstory which was also basically true for the 2012 Mongoose edition excepting a random gender flip. Colonel Randolph Prescott was a disgraced ex-American Army officer who was in Tanstaafl City in 2298 and organised and commanded the city militia for the defence of the city. After the Kafer fleets were driven off, having no army the Tanstaafl government decided to recruit mercernaries from offworld and place Prescott in command of the new regiment, called the Tanstaafl Free Legion.
There is a whole arc featuring them in Kafer Dawn (republished with minor changed in Mongoose's French Arm Adventures, and so "Mongoose canon"), and plot points in the Aurore Sourcebook pointing to the TFL eventually staging a military coup d'etat.
The Tanstaafl Military consists of two groups, thus:
Tanstaafl Regional Defence Militia, formed from:
Tanstaafl Rural Police - about 300 from a pre-invasion force of 1,000 remain
Tanstaafl Metropolitan Police - about 1,800 in Tanstaafl City itself
6x Regional Militia Regiments - about 9,000 men, who lost most of their heavy weapons fighting the Kafers in the Equator River Valley
and the Tanstaafl Free Legion - about 2,000 mercernaries recruited after the liberation.
The TFL did not exist in the timeframe, and it would have been the TRDM that any players met.
The Germans who gave the Kafers their common name were members of 2e Régiment Étranger d'Infanterie (2 REI), who were German exiles serving in the French colony of Aurore.
