Can you get all three Eevee evolutions in fire red?

Answer 1

Yes you can,

But it's kinda tricky.

You will need Eevee (if you have evolved it, it's OK) and Ditto, and a Rainbow Pass.

Then, travel to Vermilion City, and use the Rainbow Pass at the SS. Anne's location to get to Sevii Islands.

Go to Island 4.

There is a Pokemon Daycare that is capable of holding two of your pokemons.

Give the woman inside your Eevee and your Ditto.

Go for a Bike Ride, Battle Trainers for a while (max 5 min)

Go back to Island Four.

Talk to the man outside the Pokemon Daycare.

He should say, that there is an Egg.

Take the egg.

Place it on your first slot on your Six Pokemon's.

Ride across the map with your Bike. (it takes about 9180 Steps to hatch)

And then, you will have a lvl 5 Eevee!

Good Luck!! ^^