Take precautions using DE, even food grade. I use it and it's awesome for some applications, but I think being educated on the risks is important so you can make your own choices.
Read the label or check the MSDS sheet, and check the
amount of
crystalline silica. Not all food grade DEs have the same amount; it depends on where they are mined. Go for the lowest amount you can find! 1%+ crystalline silica requires special labeling warning consumers of the danger, and food grade DEs are going to be below that. I have found different brands vary greatly, with numbers like .8%, .5%, and .1%.
The risk is from breathing it, and the scariest risk is silicosis. Silicosis is accumulative. It doesn't happen right away, it is something that happens years down the line in (though there is an acute form). That means any you breathe stays in your lungs forever. It builds up and starts to cause problems -- scarring in the lungs. Carefully using low-crystalline silica food grade DE in your house is a low risk, but people are usually exposed to silica through other sources as well, so it's something to be mindful of.
Amorphous silica, the main component of Food Grade DE, is considered
safer, but it still causes lung irritation. This can be dangerous for anyone with compromised lung capacity, like asthma, COPD, heart failure, or other health issues. Anything that irritates the lungs can also be dangerous for birds, whose lungs are so much more sensitive than ours.
Also, although it's considered low risk to cause silicosis, studies have shown that prolonged inhalation of amorphous silica may cause changes in the lung, such as alveolar epithelialization. Basically, studies have not established that it is safe, or that crystalline silica contamination is the cause of these issues, so OSHA (Occupational Safety and Health Administration) does place a
Permissable Exposure Limit (PEL) of amorphous silica of (80 mg/m3)/(% silica). (So for dust that is 100% amorphous silica that translates to 0.8 mg/m3.)
Also, as it is extremely porous, when dry it will absorb oils and moisture from skin, through capillary action. For some people that might be a good thing and it's used in cosmetics for that reason, but it's also known to cause dry skin and skin irritation for some people, and animals by disrupting the natural balance of lipids on their skin.
I use DE! But I never use it in a way it can get kicked up into the air. I don't use it around my parrot, who can kick up a lot of dust when she flaps her wings. I use it in static locations as a barrier, nowhere it will be disturbed or hit by a draft. When I am applying it, I wear a properly rated breathing respirator. Also, per OSHA’s and others’ safety guidelines, I always wet down any dust that may contain silica before cleaning it up, no dry dusting or sweeping.
Because of owning a bird, my severe asthma, and background in ceramics, I am just super aware of the dangers, I think! My precautions may be overkill, but I prefer to err on the side of caution with my and my parrot's lung health. Haha.
I primarily use it to keep mites out of my isopod cultures. I have tried it against infestations of sugar/odorous house ants with no luck, unfortunately. Poison traps, secured where pets absolutely can't get to them, are the only thing that have truly worked on ants, for me.
DE will not work against bugs when wet. That means if you’re using it in a damp location where it doesn’t dry out, it probably isn’t going to help. Even high humidity compromises its pesticide effect. (This is why, despite manufacturer claims, studies have repeatedly shown it ineffective as an internal wormer, and it doesn’t kill animals that produce mucus like slugs, earthworms, and snails.)
Also, just in case, for anyone who has cats,
Avian Insect Liquidator, the bird-safe bug spray, is not cat-safe, so don’t use it in a house with kitties. It’s super toxic to them! It's a good choice with just birds and humans in the house, though, I know a lot of people who've used it to great success.
The earwig in your house, at least, was probably incidental, if that’s at all reassuring!
Thankfully, earwigs do not cause infestations inside a house. Earwigs need soil to breed in, as the mother earwigs build a nest in the moist earth, and actively raise their young. If she’s disturbed, she’ll carry her babies to a new location like a mother cat carries kittens. I’m terrified of earwigs, but I’ve been trying to get a handle on it. Hahaha. Now, at least, I can be the one to put a cup over it and take it outside, instead of calling my SO to help me. XD
For fruit flies, I put a jar with an inch of ACV in it, and a drop or two of dish soap. The dish soap breaks the tension of the liquid surface, so that fruit flies that land on it fall in and drown. It works super well, and is very safe around pets and other animals. If it’s in a room with loose birds, I’d close it with a lid with a small hole in it.
Since you poured ACV down the drains, keep in mind that fruit flies sometimes breed in drains, and the ACV is just likely to attract them. I suggest pouring boiling water down the drains as well.
I hope the dehumidifier works! I think tackling the underlying problem is the best bet long term. If you can get a digital hygrometer (humidity gauge) then you can try to find a good balance between dry enough to make your house inhospitable to cave crickets, and humid enough for bird health. They cost about 9 bucks or less at a pet store. The dial type are rarely accurate without a lot of fiddling, so go for the digital type with a probe. You can identify problem areas in your apartment that way, as well.
so now I'm super paranoid. I definitely don't want to deal with that. I haven't slept in almost 2 days cause I'm scared somethings gonna crawl in my bed at night or be in the birds cage. I am saving to board the fids for a couple days at a vet so I can have someone bomb and spray. I seen one of those things you posted, spiders and freaking flies have been bad around my area.
luckily it shouldn't have laid any eggs, they usually lay in spring and hatch by may so I'm hoping there's no eggs.
).
NOT fun. 
