If there is a different width, there is likely a different offset. This is a problem as in emergency situations, vehicles tend to pivot around the odd tire - and the more different it is, the stronger that tendency. Offset would be a major difference.
I’d recommend you scour the junkya… er … recycling centers for stock wheels that exactly match. The cost will be low and you won’t have to worry about the wheel being different.
On ebay, you can ask the seller about the hub bore size. The adapters you linked to are for the offset. The adapters that Nevada linked to are what I was referring to. I don’t know if I would care for plastic hub adapters, but the metal ones are really expensive. The hub adapters usually don’t carry the load however, that is done by the lugnuts. There is a small amount of play with the lugnuts so it is important to have the hub adapter to keep the wheel properly located until the lug nuts are torqued down.
Honestly, you need to find an exact replacement rim or get your current rim straightened or buy 4 new rims with adapters as needed. One other option would be to by two of those replacement rims you are looking at on ebay, get the proper hub adapters and use them on the back only. The effect on handling that Capri Racer mentioned will be minimized that way.