Landcruiser axles front and rear have passenger side diff off-set and matching t-case output off-sets (except some reeeeaally old ones have centered rears). I believe mini's and runners are centered rears (and centered rear t-case output) right? Anyway, I don't know what width minis and runners axles are, but heres cruisers widths:
J40/45/55--1415 mm front, 1400 mm rear
J60/62--1485 mm front, 1470 mm rear
J80--1534 mm front, 1539 mm rear
Anyway, you asked if axles from Landcruisers will work under a toy pickup and to that I say, that depends on how much work you want to do. If you want them to just bolt up, it's not gonna happen. If you wanna know anything more specific, ask away and I'll do what I can.
Edit: Oh and are you asking when mini's lost the solid axle front or when Cruisers lost the solid axle front? Cause if you meant Cruisers, they lost them with the introduction of the 100 series in 1998.
And I'm talkin' about USA Cruisers here. Other countries might be a bit different...