We recently lost our other Basenji (both lived to almost 17).
Our sons had this painting done for us. The position is a little funky on Rio, but overall, the artist captured their likeness.

Bad timing as we just had to make that decision a few days ago (well, the vet confirmed the direction).

She was 16 last Christmas Day, so almost 16-1/2.

We’ve been dealing with exactly what you listed (less the seizures), and what finally happened is she kept falling/barely could get up....and after a day, we realized she couldn’t open her mouth. She’d walk to the food/water area and stand over the bowls but not eat/drink. Poor thing. Once we realized that, we went to the vet the next morning and one look at her, the vet said those terrible words...“it’s time”:(. Which we knew.

This is our 2nd B. First one made it just over 17!

It is no fun and sorry you have to go through it soon.