Does anyone have a place for me to start? Board to buy? set up for multiple photocells? some sample code for it? Def a newb at arduino
IF you're going to do this yourself then spend real time just learning how to do things and what is possible. That could take months.
IF you're going by help then resign yourself to not knowing a lot of what you're doing.
Spend a lot of time planning and modeling different ways before you buy anything but a development board and some starter components. Even then ... Shop. The only corner you shouldn't cut is to buy the dev board from Arduino to support the IDE and forum. It's a 1-time thing unless you get into having different dev boards. :D
You won't need much of a processor for what you want but in development a standard UNO should do fine.
The same UNO can be used later to program smaller, far cheaper chip(s) that your final in the field unit(s) use.
No kidding, the UNO main chip runs about $2.50 and can run stand-alone with a few cheap components. An ATtiny costs less but has less pins, memory, flash and not all the capabilities of the UNO chip just to save a buck.
Light detectors are a few for a dollar if you shop but the motor bits depends on how you do it. The UNO can easily trigger a relay that will switch clear up to 10 Amps of 240VAC or a lot of DC on and off so if you can figure out how to work the lid with limit switches and maybe sensors so you somehow don't kill Bambi then you won't need a motor controller and code for that. Perhaps some fail-safe thinking would be in order?
But look and learn first. You can make sensors that will know when any animal is close, like capacitive sensors that will pick up a deer or bigger at 3 or more feet if you tune them right. Acoustic guitar disk sensors (piezo) could tell if something is scrabbling in or at the box.
Infrared leds and pickups to tell if something is between or reflecting off might be good but some animals can see those and might mess with the led(s). And forget ultrasonic distance sensors as they don't work well on hair, fur or wool.