I plan on using on-off toggle switches to individually control 16 servos. I have a MEGA2650, and a PCA9685 to do that. I also want to use two leds for each servo to indicate position (min and max) and want to use an Elegoo 2.8 inch Touch Screen (Not sure how yet) MY question is can I do what I want with the hardware I have or do I need more hardware. I have Wall Warts for MEGA power and Servo Power and I am running the IDE on linux and using a USB Port for Sketch loading. Once I have the hardware question worked out, I'll tackle the code. I'm a hardware guy, so that will come after I know I have the hardware to do what I want. Thanks
The usual problem with servos is power. The Arduino can control them, but you need to provide sufficient power separately. Rule of thumb is an Amp per servo, more if they're beefy ones.
You're on the right track with splitting your power supplies. Sixteen servos with a wallwart may be tricky to achieve though.
SG90's 10-250ma . Using this to power servos https://www.amazon.com/gp/product/B01N7RS0NG/ref=ppx_yo_dt_b_asin_image_o00_s00?ie=UTF8&psc=1Using the power supply in the ELEGOO MEGA2650 Starter kit to power the MEGA. I also have a mini-computer that I may use, not sure yet though. once the sketch is loaded don't need the USB connection.
I don't think 2A will be enough. Easy to test though, use a meter to see how much current one of your servos pulls when it's moving turnouts or whatever is the hardest it'll be working.