It looks very much like your seedlings could be Drosera filiformis (all red).
Concerning using an F2 designation for these plants:
There are generally considered to be two sources of "hybrids":
Intraspecific - involving plants of only one species, i.e. different clones or cultivars of plants considered to be the same species.
Interspecific - involving plants of different species or genera (Intergeneric)
Most often filial generation is used to refer to subsequent generations of plants sexually reproduced from the offspring of an initial hybrid designated F1 (First filial generation = progeny of Hybrid parent A x Hybrid parent B), interspecific hybrids.
It is also possible that intraspecific crosses can be considered "hybrids", however, this is usually not done in horticulture. F2 and other filial generations are crosses between or selfings of F1 or following filial generations (i.e. F2, F3, F4, etc.), only F1 are the progeny of the initial hybrid cross, whether intraspecific or interspecific in origin. The genetic effects are similar for these two groups of “hybrids” of disparate origins, but the results can be dramatically dissimilar, intraspecific hybrids usually show very minor or certain easily predictable variation between progeny, especially in F2 and subsequent segregating populations. Hybrids of interspecific origins generally exhibit much greater variation in subsequent generations, F2 and later are especially divergent showing wide variations between offspring.