In reply to what's it cost to get a custom font?:
what other characters/glyphs should I consider?
Something like the OpenType Std character set would be a good standard for which characters to include. Or the Windows-1252 character set.
• Software - Fontlab or Fontographer?
You should probably look at one of the other offerings such as, TypeTool, Glyphs or RoboFont. They are cheaper and will give you all of the required functionality.
