Laser printers do cost more. But for just black printing( lower cost per page depending) they are worth it, color not so much unless you need the advantages for a color laser.
Multifunction lasers can be pretty big and expensive. I'm don't really like multi functions that much because if for example the scanner breaks, now you just have a big printer.
You can clean print heads but since you don't print a lot it doesn't make sense to buy a printer that uses print heads. The cost of ink is lower but you have to figure in the cost per page. It would probably be awhile before you would have to replace the print heads since you don't print a lot. What a mean, in terms of a lot might be 800-1000 pages a month. Which isn't much for some people.
Also you have to consider that manufactures have expiration dates for their ink, They have chips on the cartridges that tell your printer that the ink is old. So if you don't use it all up before it expires then you can't use it.
Cannon makes good printers, why are you considering those printers? Just because of ADF? If ADF is important and it gets heavy use, you may want to consider a separate ADF scanner.
Anyways, I hope this helps!
the Prisoner.