The brownish stuff you see coming out on the q-tip may just be normal ear wax. Ear mite 'debris' resembles brownish black coffee grounds, so if what you're seeing on the q-tip is just brownish and not three dimensional, I believe it's ear wax.
The cat's ear canal is 'L' shaped, so technically, the q-tip would have to 'turn a corner', in order to reach/touch/damage the eardrum. However, it's not advisable to go in that far, when you're cleaning your cats' ears. The way you describe it, you're doing it absolutely the correct thing, in how you're cleaning your cats' ears. The little 'knobby' protrusions, or as I like to call them, the 'nooks and crannies' inside the cat's ears, can be cleaned around, gently, with the q-tips as you've been doing.
Mites would cause intense itching, and if your cats are not exhibiting this symptom, plus, the brownish stuff is NOT like coffee grounds, I would think that your cats do not have ear mites at this time.
The organizations below, might enable you to find a lower-cost vet or one who might see your cats free of charge, if you have extenuating circumstances:
---this is a credit card for veterinary visits and medications and might be of use for you at this time, as it enables you to pay out the vet's fee in installments, but the vet gets paid up front by the company.
Mites can't really get into the eyes or nose, and what you're seeing is probably just 'normal' debris that accumulates in some cats' eyes and noses. Some cats are more prone to develop eye and/or nose 'dirt'. As long as the dried up discharge is brown and not greenish or yellow and is not accompanied by sneezing, swelling of the eyes, lethargy, inappetance (which are all symptoms of an upper respiratory and/or eye infection), just continue to wipe away the brownish stuff with a warm, moistened cotton ball, and always wipe AWAY from the eye, towards the nose, and use a new cotton ball for each eye, each time.
When you bring your cats to the vet, they'll be evaluated and you'll be told whether or not they ear mites and/or any type of infection in the eyes.
I hope all will be well with both your furbabies!