Tell the neighbour she is welcome to phone the police and file a noise complaint. 

In my opinion, obtaining a minor variance should not be an issue because it would conform with most of your neighbours on the street.Your home is on a fringe flood plane, which should be easier to obtain than a permit in a full flood plain.

Most people are working during the day, so when they get home...kids are gone from the school and you have no neighbours across the road. 

Our neighbour there has complained about him being loud. 

For example, they might increase or decrease the price if yours has one more or one less bedroom.If one house is straight out of the 70s and the neighbouring house is fully renovated from top to bottom, they will make some level of adjustment, but for something as simple as a kitchen renovation, it likely won't make much if any difference in an appraisal. 

What kind of hurdles could I be looking at with renovations and dealing with the neighbours? 

Being buy/fix-and-hold investors we have insufficient acquisition volume to justify this cost, so we usually resort to canvassing neighbours and/or bird dogs. 2) Are there any other free online sources where I can post my ads or contact motivated sellers other than Craigslist?

Talk to the neighbours and see if they've seen any activity. 

One of my neighbour was interviewing the first and only billionaire of my country, who has his own real estate empire.

I travel quite extensively and have settled in for an Oregon beach house instead of one in Portugal, Norway,  Greece or elsewhere.