Fruehuaf driving me nuts

How’s it going fellow drivers I have a really old I believe early 70s Fruehauf end dump trailer. I need to replace or upgrade the old inboard style hubs. Been looking everyone and people are saying the old inboard style hubs are obsolete no uses or makes them. Time to upgrade right? Well the problem I’m having with that is the axles on my end dump are tapered on each end.

so I have a few questions? If I was to swap out both my axles, would they have to come from an end dump trailer? Or could I use any ol axles from any sort of semi trailer, as long as they’re the same width?
Do they have to be same brand (Fruehauf)? Also do they have to be somewhat near the same “age” my trailer is from early 70s say I find a tandem from 2010 would I be able to use that? Or would I be better off using something from say the 90s?

pictures of what I have

 

Thank you for the reply I’ll get measurements tomorrow. Axle tube is round, spring suspension