Hello generaly it is possible.
To implement delay you need to just do a meaningless calculation so as to waste cpu's cycles
for instance a for loop .keep in find that you need to determine the cpu operating frequency
for a uno that is 16 MHz which mean that it can do 16.000.000 simple operations in 1 second
this way you can find how many iterations a for loop has to make in order to produce appropriate delay.
To answer to your second question,
as far as i know timers are by default shut down and you need to awake them by setting their control register and global interrupt register.So i dont think it will be a problem.
Anyway you can shut it down easily by writting TIMSK0 = 0x00;
Generaly you can use all timers to generate interrupt (intterupt on compare mode or overflow) loading the appropriate values on them.
However if you are not planning to use millis anyway, you might as well consider using timer0 to implement
interrupt at 250 ms .This will cause:
millis to malfunction but you will not use it so no problem here
to keep free timer2 which can be used for generating pwm and is also being used from other libraries,like servo