Theoretically it can be replaced, but please note that the two voltages are different. The No. 1 battery is 1.5V and the 18650 lithium battery is 4.2V. One 18650 lithium battery is equivalent to three AA batteries connected in series.
Note: The battery has a specified maximum voltage and current. If the maximum voltage or current is exceeded, the charger will be damaged.
Emergency lights have different specifications. You should clearly see what their operating voltage is. If it is 3V you can use it as the overload issue has been resolved. as long as if the firelight becomes visibly dim, it is necessary to charge it. Don't force it to continue using it until it flashes. This is equivalent to reminding you that it is close to the excessive discharge voltage. Also you said it should be 18650 not 1860.