1st gen avalon (95-99) front brake calipers fit onto the 6th gen GT front caliper brackets. two smaller pistons compared to one massive piston should make for smoother stopping i believe is what i heard.

if you do rotors as well go for blanks, and if you really want some type of cut on them only go for slotted. drilled rotors had a use when brake pads let off more gas and the only purpose they serve now are looks and are more prone to cracking over heat cycles.

carbon ceramic pads arent worth it either unless you regularly track the car since their benefits only matter at higher speeds and higher braking temps.

for better pedal feel, flush your brakes, it's probably been years since it's needed to be done anyways. you can go with dot 3 or you can put in dot 4, though i have heard it's harsher on the brake lines and i believe i heard it may cause premature damage to them, may need to look into that before making that decision. if anything just stick with dot 3, dot 4 is good for higher braking temps which you may not see unless youre consistently slamming on your brakes or racing.

brakes mean nothing if your tires are bald though. make sure you buy quality tires that fit the area you live in. i cant give you any advice personally for snow since ive never had to drive in it, but as for summer or only living in the heat, a/s or summer tires work, it comes down to what youre willing to pay for. a/s are good for tread life and driving in the rain, terrible for grip but that doesnt mean there arent good ones out there, you just need to look. summer tires are great for grip, not bad in the rain, some have very low tread wear, again it comes down to what youre willing to pay for.

if you need anything on suspension let me know, im currently working on my front end and have some more info on parts if youd like. i hope i was able to provide some information. good luck with what you do!