The quality is not what they once were. You'll see if you search through that these are often warranty phones that were repaired with non standard components. The biggest issues have been the OLED spec screens replaced with lcd ones and non first party batteries. I don't care about the battery one but it means you get a non removable warning unless you get the battery flashed to appear first party. And you lose the health monitoring feature for your battery. It's not in all of them, but it has come up. So far the battery one I have rarely seen. There was a spat of the screens being lcd. It's possible the current batch are better. There's no info available from me searching anyway.

You can pay in advance but if you were to change to a plan not compatible with the tab, get another phone on tab, or leave, you'd have to pay the subsidy difference as well.

I'd look closely at if it's an OLED display and if you get any “non genuine”warnings and decide if youre ok with it.

There also are options for choosing if you want what quality of phone is available. Down to good, you're most likely to encounter the above mentioned

To clarify #2, if you get the CPO Phone on tab you will need to pay off the tab and any applicable tab bonus.

https://www.koodomobile.com/en/help/Tab-bonus

Let’s say I paid off my Tab balance six months from now and still stayed w Koodo for the remainder of the 24 month period. Are you saying I would have to pay the Tab Bonus amount too in that case?

At the time of your upgrade or cancellation, if you have an outstanding Tab Bonus balance (when it has not been 24 months) then yes you will need to pay that back.

But if it has been 24 months and you tab was normally paid off, then your tab bonus should also be zero