How to power multiple LEDs with a microcontroller
I see no reason why you would not be able to light 30 LEDs.
ATtiny85 only has 5 pins for use (unless you want to use the reset pin as well in which case hell will cover you). So with charlieplexing you are going to be able to address 20 endpoints. (where each endpoint might consist of multiple LEDs)
But beware. You CAN address 20 endpoints but you CANNOT light every combination simultaneouly. You will have to work out if there is a constellation that allows you to light all lights you want in the same time or you will have to use one of the timers to toggle between different lights. I don't know how well it works thou.
I have managed to use a timer on an 8MHz device to drive 4 LEDs at 400Hz directly without charlieplexing and not using PWM. So I assume it will be possible but might be flickering.
It would definitively be easier. I always recommend to stick to things that are well known and widely used. That would fit your ATmega32U4.


Make sure you layout your LEDs and think how you want to address them and if it makes sense to join multiple LEDs to one pin and toggle them at once.