As per Canoeing books, advice I followed:
one long sleeve shirt, roomy, sleeves that
can roll up. I sewed extra cloth too cover
the hole at each wrist to keep bugs out.
My first shirt was a almost canvas, for
durability.
The durable canvas-like material was too much,
too hot, and did not feel good against skin.
My next 2, were over-sized dress shirts, one
cotton blend and one 100% cotton. Both worked;
the cotton-blend felt smoother on the skin, but
it had a little more stink and retained that stink,
whereas the 100% cotton could be washed
effectively.
Though I have canoed elswhere, my total North-Country
canoeing experience is only 2 trips. 1 trip to WI/Minn.
and 1 trip to Alberta, both trips in summer:
it got hot, and I wore a light golf shirt, most days,
on the river. The collar is very useful even though
I had a full sized white handkerchief. Extremely wide
brimmed boony hat, like a Tilly or knock-off is great.
One shirt for 3 seasons seems too minimalist to me.
I would take the 2 shirts ( 1 golf, 1 dress) in summer.
If you are going to be wearing many layers,
consider that 100% cotton "grabs" and thus restricts
movement. It can tire you really fast.
Since, in each case, I was canoeing during a very dry
spell, skeeters were only a problem at night or if
walking in deep forest. They were never a problem
on the river.
Do not forget sunglasses or clip-ons. Avoid bright or
reflective colors on your gear packs ( or canoe covers,
if you use them, I did). The reflective colors will burn
your eyes, face, and neck. Ding, Ding, Ding, it just
accured to me that Ontario is likely to be much cloudier,
than where I went.
Good luck on your adventure.