Good replacements for candles include electric candles, or otherwise lights. Personally I would take a preference to the electric candles as they are intended to look like real candles (and even flicker like them) as opposed to say a flashlight which will give a steady stream of light.
Incense can be replaced with many things. I often use a few drops of essential oil in a small bowl of water on small altars that I do not want incense or candles on. You can also use a reed scent diffuser, and electric oil warmers (this has really come up in popularity of late). You could even put diffuser oil in a small bowl and use it that way. In the past when I wanted to freshen up a house, I've even put a bit of the Frebreeze inspired Mr. Clean in a bowl and let it sit for about a week. It freshens the air and smells nice too!
You can also just keep your eyes peeled for other substitutes, as people are constantly coming up with new ideas on how to get around fire risks. :)