Middle guy holding...clarinet?

It's a bloody euphonium

Possibly …. They were very popular way back then… before they became lamps

Left to right- flugelhorn?/mellophone?, tuba, unkown, euphonium, trumpet

Edit: that's a big ass trumpet too, it might be like a weird tenor horn or something.

Thank you!

It's hard to pin down exactly for me because horn design has changed so much since this photo was taken. The smaller horns on the far left and right either wouldnt be found at all in most modern ensembles or they would be configured differently, and I have never seen a tuba wrapped that way.