You have yourself a real project there. You are dealing with either
raised grain from the stripper being washed off, or the stripper ate
into the wood a bit, leaving it rough. In either case, you can use a
sanding sealer, probably more than one coat, sanding lightly between
coats.
Are you going to paint, stain, or just clear finish these chairs?
Have you estimated the time it will take to do the refinishing,
compared to the cost of comparable new chairs, and found it is in fact
worth you time (at whatever rate your time is worth)? Frequently,
unless you are dealing with antique restoration, it's not feasable.
If you are restoring antiques, do you know what the original finish
was, and can you duplicate it well?
Perhaps this is a family heirloom, in which case the sentimental value
of the chairs overrides the cost of refinishing them (labor of love)?
Just a few things to think about, hopefully before you invest a lot of
time in this.