Powering Arduino with USB & Adafruit MiniBoost independently

Hi, I'm trying to power my project from an 18650 battery using an Adafruit MiniBoost to supply 5V, 1A - tested powering the 2 steppers and 1 solenoid from MiniBoost while Arduino is powered from computer USB and it's working.
Now I need to power Arduino from the MiniBoost and I'm having trouble understanding how that's going to work.

I want to be able to plug the USB for programming. My assumptions are:
•I don't want USB 5v flowing to the MiniBoost
•I don't want the USB 5v/Arduino trying to power the steppers & solenoid which pull 500mA - 1A if the 18650 is disconnected. (Would this damage the PC, Arduino, both? Or nothing, just not work?)

My guess is to add a diode between MiniBoost & 5v pin on the Arduino. Would this be the solution?

That will work provided the controller runs from some 4.3 to 4.5 volt. The diode will lose some voltage.

Powering 2 steppers and a solenoid from only 1 amp power source looks bad to me.
Post links to steppers and solenoid.

The solenoid would only be activated for some milliseconds and never be activated at the same time as the steppers. Also the runtime of the project is also relatively short, maybe a couple minutes at a time maximum; never continuous hours of operation.

•2x Steppers are 28BYJ-48 which are drawing about 150-200mA each if I remember. (no more than 500mA together)
•1x Solenoid is product ID 2776 on Adafruit which draws about 1A on activation then settles to about 900mA. Mini Push-Pull Solenoid - 5V : ID 2776 : $4.95 : Adafruit Industries, Unique & fun DIY electronics and kits

Since the solenoid has an initial 1-1.1A draw on activation I was thinking to add a capacitor. Would that help?