Question: Why not rebuild the engine than to change it completely ?
Suggestion: 1995/6 LC-II SX5/EX5 Prado could be narrower than what you have currently. It is 73.6 inches wide (2.8 inches narrower than the 100series), dont know how wide the 90 is (even though I have one)
Keep your 90, install rock rail side steps and ARB bumper upfront.
When you find a snorkel, let me know too.