うちっちーの中にはグロスやらなんや
Befor examining the given sentence, let's study the following phrases.
(1) なんやらかんやら (なんやら-かんやら)
(1)' 何{なん}やら彼{かん}やら (何{なん}やら-彼{かん}やら)
(2) なんやかんや (なんや-かんや)
(2)' 何{なん}や彼{かん}や (何{なん}や-彼{かん}や)
(3) なんだかんだ (なんだ-かんだ)
(3)' 何{なん}だ彼{かん}だ (何{なん}だ-彼{かん}だ)
(4) なんだかだ (なんだ-かだ)
(4)' 何{なん}だ彼{か}だ (何{なん}だ-彼{か}だ)
Note: We usually don't insert a dash/hyphen like that in the parenthesis. I only place it to tell you to pronounce the phrase with making a short pause at the dash is placed for your convenience.
These phrases all has the same meaning like something or other; one thing or another; this or that.
does "グロスやら" means "lip gloss and things like that"?
Your understanding is correct.
I think the writer wanted to say like:
"There are various things like a lip gloss and the like in the うちっちー pouch".
うちっちーの中にはグロスやら 、 なんや かんや入{はい}ってます!
やら in グロスやら comes from the usage of やら in "(1) なんやらかんやら" that means like "and the like". So I said your understanding is correct.
And なんや in グロスやらなんや comes from "(2) なんやかんや" by omitting かんや.
I think グロスやらなんやかんや is more formally natural than グロスやらなんや, but the writer chose グロスやらなんや because she thought the formal expression sounds or looks a little tedious.