What you're describing is 2 sets of rear springs.......that won't work. It's either LC 9 Wraps, or OME.......I'd go with the 9 wraps, and then do the Tundra Strut Assemblies.
As for using the entire front end off a Tundra....I've never heard of this, and if I had to guess....it probably wouldn't work either.
Best and most economical route to fit 35's, without any MAJOR modifications:
- USED Strut Assemblies from a 2000 TRD Tundra 4x4 Access Cab with a Topout spacer from Toytec and your 4Runner Top Plate.
- Diff Drop Kit from Toytec
- LC 9 Wraps with some LC rear shocks
- 2" Body lift
- maybe some light pounding and cutting, but probably not.
Now that being said, you could go with some Toytec Coilovers that are adjustable, those are really nice, but cost more than the Tundra Struts I got.
Your proposed method would most likely be more labour intensive, and I don't even think the components would work. Sure the suspension parts like the struts are the same as I proposed, but the suspension arms, and the rest including the front hubs and diff, won't be the same........