Ok, I've got a lot of info here... so buckle down and bear with me. LOL
1- For your 4yo, I STRONGLY reccommend putting him back into a 5-point harness. Most kids are not ready for boosters at his age and are much safer in harnessed seats. Most, if not all 4, 5 and 6yo's just don't have the maturity to sit properly in a booster seat, will put the shoulder belt under their arm, or behind them. At this link there is great info on specifically why harnessing past 4yo is safer. Please check it out:
http://www.kyledavidmiller.org/pages/4211/Car_Seat_Safety:_5-point_Harness_is_Safest.htm
I also wanted to add that if you feel like harnessing your 8yo as well, there may still be higher weight harnessing seats out there that will fit her. With her it really will depend on her height, her weight is well below the limits on most higher weight seats. But if she is mature enough to pass the 5 step test then she should be fine in her booster. The 5 step test is:
The 5-Step Test.
1. Does the child sit all the way back against the auto seat?
2. Do the child's knees bend comfortably at the edge of the auto seat?
3. Does the belt cross the shoulder between the neck and arm?
4. Is the lap belt as low as possible, touching the thighs?
5. Can the child stay seated like this for the whole trip?
2- "
And can you explain which car seat is LATCH'ed or Anchored to the passenger seat? Do you mean front passenger? Or the LATCH anchors are behind the 2nd row freely/independantly from the 2rd row seat?"
For the latch system in the 2nd row middle seat, there is the anchor for the top of a forward facing car seat, but not on the bottom sides, which is what i need for the rear facing seat. "
There are no LATCH anchors that can be used in the center position in a 2003 Pilot. But double check me on this, I don't have a manual only the internet.
It will be in your vehicle owners manual under LATCH. The LATCH anchors are the ones in the seat bight (where the seat bottom and back meet). I'm am 99% positive that what you think are the center LATCH anchors are actually the outboard position anchors. You can ONLY use these on the driver and passenger side outboard positions. And you cannot in any way attach more than one carseat to a set of anchors. Anchors also have weight limits, so if you do install a seat with LATCH- you need to re-install it with the seatbelt when the child reaches the weight limit. (I'm pretty sure that Honda's LATCH weight limit is 40lbs). You CAN however, use the top tether anchors in all seating positions that it is available- still only one carseat per anchor. You can also find out where all of the top tether anchors are in your vehicle owners manual.
On this same topic, that I know of, there is no vehicle that has top tether points specifically for tethering a rear facing seat. Most carseats do not allow for tethering rearfacing(RF). The only seats that allow this are Britax seats and the Sunshine Kids Radians. If you do get one of these seats, then they will provide you with a d-ring and instructions to create a RFing tether point.
Still with me?Ok, now for seating and carseats.
I would reccommend putting your 8yo in her Turbo Booster in the driver side third row seat.
I would also put your 4yo inthe 3rd row in a harnessed booster. The Britax Frontier and Graco Nautilus are both highly reccommended. The Frontier harnesses to 80lbs and then converts to a belt positioning booster up to 100lbs. The top harness slots are higher on this than on the Nautilus, so it would last him longer (most kids outgrow by height, not weight). Frontiers run about $229. The Nautilus harnesses to 65lbs then converts to a high back, and a no-back booster. The no-back booster portion is good for 9 years instead of the customary six, so you might get a little more use out of that portion, especially with the younger child(ren). It runs about $150 at Walmart.
Now, with your 2yo and new baby there are a couple of options.
I would suggest that you turn the 2yo back rearfacing. He/she is under the RFing weight limit and it is so much safer to RF. The American Academy of Pediatrics now reccommends that all children ride RFing until at least age 2 or to the limits of their carseat. This is your choice, again, if you want more info let me know.
I would say put the 2yo behind the driver. You can create the RF top tether point here (if you decide to RF) and it will be easier to get her in and out in this position. This seat will also be harder to manuver around so having it on the inside will be easier as well(when moving around/entering from the passenger side door, since the 2nd row folds down there).
However, when you graduate the baby out of an infant seat to a convertible that is RFing, I would move the 2yo to the center(if forward facing) and put the baby behind the driver.
Which means, that if the 2yo is RFing behind the driver, then put the baby in the center 2nd row. If you are using an infant seat you won't have a top tether to worry about and the most common infant seats are a snap to install with seatbelts, since you catch use LATCH in the center. With the infant seat in the center, you'll be able to fold down the pass. side to access the 3rd row, even if the base is already in there it should work, and you will have a lot more room for everyone to get in if you put the baby in last.
Now the exceptions are if both the baby and 2yo are RF AND in covertibles. it doesn't matter who is where as long are you have one in the center and one behind the driver. Even if both end up having RF top tethers you can have one in the center(with the seatbelt of course).
For your 2yo: Since I don't know what kind of seat you have I'm just going to suggest some, let me know if you want more info either on your seat or any other you find.
Look at:
First Years TrueFit (RF35lbs, FF65lbs- highest top harness slots and super tall shell)
Sunshine Kids Radian(65,80,XT) They all RF to 40lbs (since Sept. 08) and FF to 65 or 80lbs, has RF top tether
Complete Air- RF40lbs, FF65lbs, very tall shell, side impact protection
Graco MyRide 65- RF 40lbs, FF65lbs. similar to Britax Marathon in size
Britax Marathon: RF 35lbs, FF65, has RF top tether, side impact protection
For the baby, if you need a new seat: I'd look at the Graco SnugRide 32, and Chicco Keyfit 30. They are larger infant seats with higher weight limits. The basic Keyfit and Snugride are smaller and have lower weights, but are just as easy to install.
So, quick overview, 8yo in turbo booster 3rd row driver side, 4yo harnessed booster 3rd row passenger side, 2yo RF or FF convertible 2nd row behind driver, baby infant seat center 2nd row.
The only major preblme I see with this is that you are going to have limited storage space for stroller groceries etc. I would suggest getting the most compact stroller that meets your needs and the largest plastic bin(s) w/ lids that will fit in your cargo area. When you need to carry groceries AND the stroller put the groceries in the bins, and store the stroller on top. Keep in mind you still want to secure the stroller etc. You could also place some groceries in the front seat if you had to.
Wow- that's a ton if info. I hope you got it all and I didn't over whelm you! PLEASE let me know if you have ANY questions...I'll try to be much simpler next time. 4 carseats and seating, plus storage is a lot to cover!