# the man clothed in linen

"the man who was wearing linen clothes" or "the angel who was wearing linen clothes" 

# upstream along the river

Possible meanings are 1) the angel clothed in linen was above the river or 2) the angel was further upstream along the river.

# these amazing events

At the time when the angel spoke to Daniel, none of the events in this vision had happened, including the events in the vision from chapter 11.