Hi Ashlynn! Great question!
Today, more and more churches and temples are introducing features like electric candles, complete with flickering flames. Electric votive candles have long been in use in military chaplaincies.
For burning incense, it really depends on your smoke alarm detector. You’d have to test it. Some of them, if you don’t burn too much under or next to smoke detectors you should be fine. Be sure to open a window!
Another option is sage spray for cleansing spaces! Can't Burn Sage? Try This!
Remember that the Magic is not in the ingredients or the tools but in the Witch! 
Every ingredient has a substitute as long as your intentions are clear and in line with your will.
For more ideas, read this post too! Altars in Apartments