Should a laser printer be plugged into the same wall outlet as the UPS?
Short answer: that makes no difference. Houses are typically wired so that all of the outlets in adjacent rooms are daisy-chained and connected to the same circuit breaker. Sometimes, several breakers are used to split the outlets so all of them do not go out if a breaker pops. A large draw in one plug could lower the voltage on all the other breaker's outlets, but I think it would also lower the voltage on every outlet in the whole house.
I wouldn't worry about it though. Appliances (in North America) are rated to run at 110-120V, and dropping from 120 down to 110 should be just fine, even lower "briefly". If you've ever seen the old incandescent light bulbs when a dryer/washing machine/electric stove is turned on, they can dim for about a second. It's nothing new and appliances are supposed to be designed to handle average things like that.
If your computer is on a UPS, that will protect it from such temporary "brownouts". The momentary voltage drop from a laser printer typically isn't enough to kick the UPS into battery mode but if it does, that's what the UPS is there for. That doesn't hurt anything.
Should a laser printer be plugged into a surge protector?
A surge protector will protect the printer from any high voltage spikes on the power line, which is valuable. It will have no effect on the printer's momentary high current draw or the effect of that on anything else.
Should a laser printer be plugged into the UPS?
Every UPS I've seen has some non-UPS / surge-only outlets that should be fine. They are not included in the power-rating (VA/watts) of the UPS, which reflects the limits of what the battery can supply when in UPS mode.
However, you don't want to plug a laser printer into one of the UPS-protected outlets. This is discussed in answers from "Why shouldn't I attach laser printers or scanners to a UPS?". Typical UPSs for home use are designed to handle the power requirements for the critical components of your system, to give you enough time to shut down gracefully. Adding the power requirements of a laser printer to that of the other components may exceed the rating of the UPS, in which case it would shut itself down just when you need it. Even if it is within the power rating, it would greatly reduce how long you could operate on the battery, which might not provide enough time to close your work and shut down properly.