Size question and cross breed question

So i have a "presumed" female BN (common brown one) about 2 inches long (not sure why but even after 2 years in a MASSIVE tank she seems to have stunted growth) and just ordered a 3.5 inch male and female pair (also common brown) to start off my breeding. Now i had planned to breed both females (i might not considering her stunted size could be genetic defect/health issue) but is 2 inches large enough?

On another note i wanted to breed a less common morph but wanted to make sure they were variations and NOT different species. So i wanted to breed together a long fin albino and a blue eyed lemon, which i have seen combinations of but not sure if it is the long fin variety of the lemons rather than the common long fin (not even sure if that distinction exists).

Also, if this is possible what would be the assumed outcome?
I have been told long fin is dominant (though that seems odd to me but i would love to know for sure)
and then i would assume albino is recessive to just about everything but then again i don't know what the "lemon" gene really is? (it almost just seemed like a "leucistic" since the color is albino-ish but the eyes are blue)

But, assuming what i've worked out is correct (long fin dom and albino normally recessive) then i would get nearly (if not all) long fin lemons with the blue eyes.

But then after considering this i realized that if the eye color is separate from the lemon color then i would assume the albinos have the gene for brown eyes in which case i would get brown eyed.

Well any input i would appreciate, genes are not really my thing haha.

Cross breeding is indeed possible, I was a 100% NO on this until the last few weeks when I saw a Peppermint Female lay & hatch with a L144 Male.
The results were L144 to Peppermints - 1:3

As for the LF/SF & the eyes, it really can be a guessing game - i am not that great in genes either...

2" is not too small at all, you may find that her growth may increase once there is a male in the tank.

Just got my new plecs^^ 1 male and 2 females (hopefully) 3.5-4 inches each and only $15 total^^
i put the two females in my 20 for now (i wasnt expecting them until next week...) and then the male in the 5 with the small female, cant wait to get my other 20 and 15 back this sunday -_-' my poor red tail cat is being evicted from his bed by one of the girls, this could be a stressful weekened for my poor fishes...
as for the male and small female, will he hurt her? the size difference is just so drastic... but i figured id have a better chance of no fights with the female in with the male rather than a larger female... good or bad choice?

I'm guessing 5,15,20 are tank sizes in gallons?
The male won't hurt her, but you just might. Based on what you wrote, you have new tanks. Or expecting them. Please, read about ammonia cycle process. Please, stop buying the fish if you're not prepared logistically. BN in 5 gal tank - that is bad choice.

ya i no, the only reason i bought them now was because otherwise i wouldnt be able to order them again for some time, but i figured they'll go in my cycled 20 and then my gold fish and mollies are going into my 75 and uncycled (to start the cycling) the 5 is just because of my fish beating up my lil plec so i separated her. I just wish i hadn't given my tanks to my friend cuz waiting on them is now getting annoying...

From an experience point of view youre doing exactly what i did when i started out, and that ended really badly.
I suggest slow down on the buying and pay more attention to setup.
You dont wanna put any type of plecs in a tank that isnt 100% cycled (6months cycle), theyre a skin fish, theyll die from the tiniest amount of ammonia, and even if theyre alright so far, when they start popping babies in a fresh tank, media will go in overdrive and youre left with a spike in parameters and lots of dead fish to scoop.

And chucking a bunch of mollys and goldfish straight into a fresh tank isnt very humane either.

I cycled one of my breeding tanks for 5months with just 2 platies and now its full of gibbiceps.
Just be patient my friend

Also be patient with the buying too, theres plenty of fish around.

My very first breeding pair died because i thought it was a now or never buy, but its not.

Good luck.

http://www.bristlenoseworld.com/t2500-crosses-interbreeding-bristlenose-updated