Asking only one person makes it a bit more difficult to get a conclusive answer, as you are never goi8ng to know which one is which straight up. Using my theory:
Q1 - Are you a liar?
#1: No
#2: No
#3: No
#4: No
#5: No
One of those statements is definitively the truth, as the truthteller can never lie. So the togglers would be lying if they said no as the the formula goes lie/truth/lie; or if it went truth/lie/truth, then they too would be telling the truth. Assuming the first formula is correct, the next question will be:
Q2: Is your answer to Q1 correct?
You will get a yes from the truthteller, but you may still not know exactly who they are, as each haven't answered their questions. But, for example, let's say it's person 1:
#1: Yes - truth
#2: Yes - lie
#3: Yes - lie
#4: Yes - lie
#5: Yes - lie
The problem with this scenario is that an assumption has to be made who is the truthteller, and all 5 participants still have to be asked.
Very tricky problem indeed.