Do I need to provide hotel bookings for the entire 90-day stay on a Thai e-visa?

I put the hotel I’m staying in for the first night for 1 night only and my visa was approved yesterday.

Just show your first nights booking as you move you will be logged into your new accommodation, as for your 90 days, just go to your local immigration office about a week before your visa runs out and extend it by 30 days 1900 baht

Look on Agoda, many refundable stays. Many you don’t even need to be charged.

First, you’re going to be applying for a 60 day Tourist Visa and then you can go to Immigration and pay 1900 baht and get 30 additional days, if approved. The current Thai Tourist Visa (TR) Single Entry is valid for 90 days from the date it is issued, meaning you must enter Thailand within that 90-day validity period. Once you enter, you are normally granted 60 days of stay, and then you can apply at immigration for a 30-day extension, giving a maximum stay of 90 days from your entry date.

Second, I know the Royal Thai Embassy in Ottawa quite well. They will not demand to see accommodation records for the entire trip. The key is that the embassy wants to see that you have a credible accommodation plan and are not arriving with no arrangements at all. Worst case scenario and they do ask, go on Agoda or Booking, reserve the nights at various hotels that allow free cancellation

You’re getting an eVisa so the changes won’t affect you.

Your return/onward travel must be within your permitted period of stay, which for the SETV is 60 days. Immigration may not check but airlines frequently do. So, it sounds like your return ticket is for a date outside of this.

You can extend your stay by 30 days at the immigration office for where you’re residing. Cost (usually) 1900 baht. You also need two passport photos.

If you are talking about the tourist visa just pick a hotel and provide their details. Be aware you only get stamped in for 60 days on that visa and will require a 30 day extension once inside Thailand. Also check with your airline whether they require a ticket out of Thailand within the 60 days

Just show first night or few nights accommodation that is normally enough

Just book free cancellation

I just book a refundable booking on agoda or booking com to generate the booking details, then cancel thereafter.

You say you have a Canadian passport, but where are you applying? Which embassy? There's only a couple that require proof of booking for the entire stay, and most of those are in SE Asia.