Suit Supply is "trendy" - skip it. Michael Kors is somewhat fashion-forward and not well-respected for menswear. Buying anything from eBay is high-risk anyway. It would be better to provide an approximate location or rely on websites such as Sierra Trading Post.
Probably something like this (incorrectly called an oxford)...
Think lace-up with a rather casual material/finish. A medium color would be better than what's pictured, though.
Between the bespoke and look, it's probably more likely to be cotton than linen. Frankly it looks like it contains some wool, making it better in most ways. Browsing, say, a Nordstrom, could lead to a better idea by hand comparison. The suit's value would be affected by its size, and frankly bespoke by an unknown maker isn't going to be worth much to many people.
The yoke looks like it extends too far out. The other questions could be tentatively answered, but the items should be brought to a tailor and his (or her) skill and attitude could be gauged by answers to those questions.
The shoulders don't seem to fit right, which is a significant issue. The sleeves look slightly long. Only an issue if the shirt has already been washed several times.
By the way, the pants look a bit tight in the seat.