There's a long-running (and highly amusing, at times) thread at Stargazers Lounge where this topic is discussed. If you want to cut to the chase, scroll down to the advice provided by discardedastro here: https://stargazerslo...-build/page/39/
You make the comment that it's "only about 90'", however that's more than enough distance to experience an induced transient from nearby lightning strikes sufficient to do serious damage to your equipment. I wouldn't want a copper run that long if I was in an area with any possibility of thunderstorms. An RF link may be a suitable alternative, but can be a lot harder to troubleshoot without specialized equipment if interference or signal quality issues intrude. Where I work, we have many high speed data links between buildings, some on mountain tops where lightning activity is common, and essentially everything is linked using fiber. One of the last links which wasn't was a serial line running through a buried conduit from a dome to its control room located less than 20 meters away. A nearby strike resulted in a peripheral card with a literal smoking hole in it the year before last.
Hah - I get around and don't even notice. Just figured I'd browse around over here, thought "hey, I know something about that.." and it turns out I've pre-empted myself...
I'd definitely do fiber for 90', for all the reasons you've listed. Media converters are cheap and pre-made cable to length is also cheap. I'd absolutely stick to singlemode though. It's much more forgiving of distance, is where all the cable innovation is happening (G.657.A2 can tolerate crazy bends, if you have a tricky install), and is just as cheap. Used to be, 10 or so years back, multimode was half the cost - these days the only time multimode is used is between adjacent racks in a datacentre or within a rack. Use duplex - again, simpler, easier. BiDi optics (which only use a single fiber) exist and work fine but are less standard so you'll pay more. LC vs SC is entirely up to you, but SFP/SFP+ modules are all LC so if that's what you're plugging into, sticking to LC is probably as good a plan as any.