Yes, you will have to go through the bag line.
I don't really know what they are looking for, but I carry about what you are describing and I always have to go through the bag line.
I have found a list of what is prohibited to bring into the parks in the WDW website:
All park guests and visitors must agree to security searches of personal property such as strollers, backpacks, purses, and camera bags prior to park admission. Disney has declared the following items restricted:
1. Wagons, skateboards, scooters, inline skates, and shoes with wheels
2. Strollers larger than 36x 52
3. Suitcases, coolers, or backpacks with or without wheels larger than 24x 18
4. Any trailer like object that is pushed or towed by an
ECV, wheelchair, or stroller
5. Alcoholic beverages, weapons, folding chairs, glass containers (except baby food and perfume), and pets other than service animals.
6. Animal Kingdom also prohibits balloons, straws, and drink lids to protect the animals.
Small quantities of food or drink (in plastic containers) are permitted. Medical devices and prescription drugs should be declared and small fabric coolers for those drugs are permitted, but it is recommended that the cooler be stored in a Guest Services locker during your park visit.
Disney also requests that guests wear attire that is appropriate. Restricted items include:
1. Adult costumes or clothing that can be viewed as representative of an actual Disney character.
2. Masks (unless dressing for a particular Disney sponsored event).
3. Clothing with objectionable material (including obscene language or graphics), excessively torn clothing, clothing that exposes excessive portions of skin viewed as inappropriate for families, and objectionable visible tattoos
I would check with Disney to make sure that the list hasn't had any recent modifications. My DW and I carry a small mesh fabric backpack (easily seen through) into the parks that security doesn't even have to open to inspect and we breeze right through (in only a few seconds).