First off: 10g is NOT enough room for 6 pea puffers, they will become aggressive/territorial as they become adults and need a minimum of 3g per a fish
. Even in a densely planted 10g tank I would strongly advice against that many puffers.
I've kept sponged over the intake of my HOB before (just cut up a thick piece of left over filter sponge I had and shoved it on) when I kept a betta so its fins wouldn't get caught/ripped. I also put a cut piece of sponge over the outflow and planted it with riccia, did great for reducing the flow to something the betta could tolerate (betta and pea puffers don't like strong flow/currents), ricca gave a nice bit of color so it wasn't just ugly hob with sponge on the outflow it was planted (also have house plants in the hob).
I will say the downside to having a pre-filter/foam cover on the intake is it will get clogged eventually with poo and plant matter/etc and reduce flow more. Best thing to do is just remove the foam at the beginning of every water change and rinse/rub all the gunk off then put it back on and do the water removal (may see some extra debris shoot out of the filter from taking the sponge off) to prevent it from getting clogged. Since I had a thick lush carpet of riccia growing on the sponge over the outflow I never saw mulm build up and it didn't shoot any loose gunk out of the filter.
I've not tried keeping pantyhose in the tank for extended periods before, I always worry about a fish getting its fins, scales, or hide (catfish) stuck against it. But I've used it to catch mulm after cleaning filters when they're turned back on, but its removed within a minute.
Never tried water bottle..not too keen on having my tank look like a littered park pond
You can look into stainless steel mesh pre-fitlters a lot of shrimp owners use them to keep from loosing shrimplets. A few pt members sell them here in the for sale section, but I cannot recall their names. I have no clue how often this would need cleaned to prevent clogging/overkill flow reduction as I've not used it myself.
You can also diy a stainless steel spillway
for the outflow and grow more plants in there for reduced flow and more nitrate absorption.