It’s better if you can do it all at once, but you don’t have to.
You can start with the front by replacing with new shocks and coils.
You can lower the rear air sensors about 1/4” to raise the rear air bags about 0.75”.
Here’s a thread that explains some of what you want:
You just got your GX470 and want to do a mild build to improve looks and off-road capability. You want to stand out over the mall cruisers and soccer moms, but want to keep costs under control. This primer doesn't consider any other repairs or basic maintenance your GX470 needs. First, lets...
forum.ih8mud.com
I’m running a 2” lift up front with Bilstein 6112s and 600 lbs/in coils. I have no extra weight up front.
The rear still has the air bags raised about 3/4”. Rear has OME 60004S shocks but seem a little stiff. I’m holding off on rear coils until I get tired of the rear air bags. The rear air bags were replaced in 2013 by PO with oem so they are relatively newer compared to 2003 ones for my model year.
Ride in rear feels jarring and bouncy when empty. Much better when loaded with gear.
In terms of tires, if you go bigger than 32.1” tall and 10.4” wide, you will need to do several modifications.
The 255/75R17s fit perfectly and are great for exploration, but a lot of people don’t like skinny tall tires and want fatter and taller 33s which will require many mods.