1) Maybe, maybe not. The longer your wort goes without your yeast in there, the longer bad stuff has a chance to get a foothold. That said, you're probably okay, just no way of knowing until it's given some time.
2) frog already metioned some ideas, so I'll just add that the temp that you ferment at will affect the flavor profile of the final brew. Higher brewing temperatures can lead to funky / fruity and heavy alcohol flavors. You might not notice the effects in darker or heavier brews, but if you're trying for a lighter beer, they might show through. On a side note, some styles favor warmer brewing temps, although 85F might be a tad warm.
3) If you have a thief, just open your lid and grab a sample to measure. If your gravity doesn't change over the course of a few days, it's done. Honestly, I never bother doing so. Just give it plenty of time to do its thing, and watch for airlock activity (or lack thereof.) One thing to keep in mind with the fermentation buckets is that their lids don't always seal completely, which can make reading the bubbles misleading.