3 across: Will it work?

I have a coworker/RN friend who has 3 kids. They are all in FF harnessed seats and her mom is going to be keeping them for a few days (friend is pregnant, long story)

Anyways- Her mom has a 2000 Taurus.
The carseats are this-
Roundabout, Marathon and an Evenflo seat. Not sure the exact Evenflo seat.
I asked her and she is looking tomorrow.
**Edited** I think its an Evenflo Titan. I compared a Facebook pic of it to google images : )

Anyways... will these fit FF 3 across?
She is worried about buying a new seat before gma watches the kids if it won't work.
I mentioned she could borrow my Radian in a pinch but we aren't that close of friends so I don't know if she will take me up on it.

She also was wanting to replace the Evenflo seat with a FF harness seat that converts to a booster. All I could think to recommend was a Nautilus. They are having baby #4 soon and I think her car seat budget is not really that high. Any recommendations that you guys can think of for her? (I mentioned Radian and Frontier to her, but let her know they were a bit pricier. I told her Nauti was a great seat and was probably her best bet.) The oldest kiddo that will be in this seat is like 4-5 years, tallish and 35 lbs. He's a sweetie : )

I think most seats will work in s Taurus its huge@

What are the ages and weights of the children?

I don't know exact weights and ages. I know the youngest is the same age as my son, 3.5. And then roughly a 4 yr old, and then roughly a 5 year old.
The 5 year old boy, the Evenflo seat belongs to, and she told me he weighs 35 lbs.

I know she has them all FF. She kept the 3.5 year old RF until "close" to age 2... until it just wasn't manageable anymore for her. (legroom etc.)

Is she going to try to fit 4kids in the Taurus on a regular basis? My recommendation would be a new vehicle. On a one-off basis she could put the oldest harnessed child up front in a Radian or a LBB with the seat pushed all the way back. But that is not something people here would recommend on an ongoing basis.

No, the Taurus belongs to the grandma. I am betting the baby will not be hanging out with g-ma much... my friend exclusively breastfeeds. And I think the g-ma lives in Kansas?
My friend drives a 2002 Tahoe

The Harmony Defender and Evenflo Securekid would also be good choices. They are more narrow than the Nautilus too. But the Taurus is wide, so her seats will probably fit fine. I used to have a Taurus and fit Regent, rd Radian, Regent!!