From the looks of bylaw, no. The lodging zoning says it is specifically
not for hotel/motel or apartment building operator. (Meaning it is not for commercial properties)
I really hear you pain about talking to the zoning / planning department. Contrary to what you may have heard, they are not going to really help you or work with you. They are there to enforce the rules. They expect you to have a perfect, working knowledge of these bylaws and to come to them only once you are ready to pay fees for permits. A lot of the planning officers at the desk and on the phones are straight out of the planning program and know very little about the bylaws and how they are applied. It can be a frustrating process with a lot of inconsistency.
You don't need to be scared, you just need to follow the rules. Just be aware that your file might be in the "questionable landlord" bin by virtue of investigation with the safe housing committee so they are probably going to be dragging their feet when it comes to providing you with answers. Your best defense here is to become knowledgeable about their concerns. The City of Calgary website is pretty frustrating to navigate but you need to become an expert on what a lodging house is.
You probably will not be turned into a commercial building because of zoning restrictions. Sounds like you spoke to someone just being flip with you. It is a totally ridiculous idea.
Honestly, you don't need to panic. Worst case, you empty out the house and rent it to one tenant. Problem solved with the planning and zoning department. I know it is a cash flow concern as well but that is what the research on a lodging house is going to help you with.
Do not expect the city to help you with this problem. Calling an architect is a waste of a conversation but calling a professional planner might be worth your time and investment. You want to search for something like "urban planner Calgary" or "municipal planning Calgary". Urban planners are experts on zoning and often coordinate that aspect of the development for (large scale) professional developers. Someone like
CityTrend. Keep in mind that there is (most likely) not big money in providing permitting for lodging houses so even they may not be overly familiar with the zoning rules.