JBL 3-way 8" speakers tend to be very good. I've got two models of that description, L212, PT800. They only need a sub for the low end.
I have never seen the HP8B, as they were made from '96~'97, before I started to look for new speakers in '99. As they were only made for 2 years, not likely you will find any more of them for MC.
But if you buy other JBL 3-ways with a Ti tweeter and 6~8" mid-bass, you might get close enough to timbre match those HP8B.
You could look for the 1990s L series models; L1, L5, L7, as I recall.