Any antenna will couple to some extent to another, especially if on the
same band... I have modeled my 80 meter antennas with spacings in
excess of 1000 feet and they still distort each others pattern... I use
relays to detune the unused antennas...
Now, your inverted vees at right angles on the same support will work
OK... I don't know that there will be a big difference in patterns, I
suspect less than a half S-unit at best... But try it and let the group
know your results...
There will be less couplilng between antennas on different bands and
while there will be some pattern distortion what you lose in one
direction you will get back in another... I would hang the antennas and
go for it... Drop us a line when you are ready to go and we can make a
sked to work you on 80...

denny / k8do