FtM TS: Female to Male Transsexual
FtM TG: Female to Male Transgender
FtM: Female to Male
FtM CDer: Female to Male Crossdresser
A FtM TS is a transman. He is fully male in identity 24/7. If it is safe enough, he'll present as male 24/7. He prefers to be referred to with "he" Him" "His" etc
A FtM TG is a much broader term. I've seen it mean different things to everyone, but I personally define it as: any person who was at one female-bodied and transgresses the social definition of femininity. This includes everyone from butch lesbians to FtM CDers to Transmen to female bodied genderqueers to everyone else in between.
A FtM CDer is a female who sometimes dresses as male. This may be to perform (as a Drag King) or in private, or just because she prefers men's clothing...