Translation:I am looking for a short young man.
There has to be a comma between "niskiego" and "młodego".
"In case of continuous text - unlike posters and leaflets - each point of enumeration is closed by some punctuation mark. It could be a comma (when points are short), a semicolon (when they're longer and including commas themselves), or a dot (when points are sentences)"
No, neuter and feminine forms are always different.
Maybe you confused feminine with 'not masculine-personal plural', which is sometimes referred to as 'feminine plural' (but that's a simplification which seems to me rather harmful and confusing). Those two versions look the same in Nominative and Accusative.
Sorry, I guess I didn't make my question clear. I am confused as to when to add the ending "ie" in the spelling of the neuter form, and the ending "ia" in the feminine form of adjectives like niski and wysoki. In the nominative case, both these adjectives take an "ie" ending in the neuter form but just the "a" ending in the feminine form (niskie in the neut., but niska and not niskia in the fem). I know that adjectives ending in the letter "k" generally take an "i" ending in the masculine nominative, and an "ie" ending in the neuter nominative, but why not an "ia" ending in the feminine nominative, and when, if ever, is an "ia" ending appropriate for the feminine instead of just "a"?
From what I know:
-bi - -bia: żabi - żabia (of a frog)
-ci - cia: koci - kocia (of a cat)
-fi - fia: elfi - elfia (elvish)
-li - -la: pchli - pchla (of a flea)
-ki - -ka : wielki - wielka, miękki - miękka
-gi - -ga: nagi - naga (naked)
-mi --mia: ćmi - ćmia (of a moth)
-ni - nia: bociani - bociania (of a stork)
-pi - -pia: głupi - głupia (stupid, foolish), trupi - trupia (of a corpse),
-si - sia: ptasi - ptasia (of a bird)
-wi - -wia: krowi - krowia (of a cow)
-zi - -zia: płazi - płazia (of an Amphibia) -y - -a: mały - mała, duży - duża
Although adjectives are quite regular, I cannot guarantee that this list is 100% correct.
In my mind two things are happening here:
"niski" - is replacing the regular masc. "y" with an "i"
"niskie" - is adding an "i" inbetween the regular neut. "k" and the "e"
... because for some reason Polish natives can't spell or pronounce the combinations "ke" "ky" (also "ge" "gy") - however the "i" is only needed for masc. and neut. here, but no change is required for the fem. - niska is fine, while niske and nisky are not.
So the "i" in this word is not really part of the root, but rather a change to some of the forms of the word as required by pronunciation/spelling rules.
Someone please correct me if I'm wrong!