Some info here:
http://aerostories.free.fr/pil_cha_fr/legloan/
As for Le Gloan going to URSS with Normandie-Niemen, the French unit in 1943 was roughly of the size of a French Groupe (or a RAF squadron), not the regiment (roughly equivalent to a RAF Wing or USAAF Fighter Group) it was in 1945, so a very low percentage of French fighters pilots took this choice in 1943.
When Le Gloan died on 11 September 1943, a total of 37 pilots had joined Normandie since November 1942. The majority were members of the FAFL since 1940 or 1941, and by this date 15 were already KIA or MIA, 1 POW and 1 wounded, while another had left the unit.