Hello,
What do you expect from this with a board based on ATTiny

Unless you taking care so much about prices. That who sounds really not a right way to have a deal for the programming by someone, hummm ?
Read the electrical specifications of the LCD screens you want to use:
Supply voltage for driving the LCD screen type 14V
Typical 80mA Supply Current
It is already 80mA on 14V, which means close to 240mA on 5V for only one of LCD screen that you plan to use.
And without dealing with many other necessary components.
This means that it's better to take a good power supply, with, at minimum, several outputs like 3V3, 5V (maybe) and 14V.
In this case, why consider taking a board based on ATTiny, when the power unit will be bigger than several of these boards ?
So, staying serious
Why try to find someone who will certainly have a big headache to make code, especially at a reasonable price, as you request. For something that will probably never work with the electrical specifications?
Electronics it's like mathematics and algebra, if you stay logical, things go well, otherwise ...