Hi Jian,
I'd say that 4th is dissonant considered in an harmonic superposition rather than as an interval wether it be in the bass or in the soprano.
In Fig.73 b. 7 it implies a chord of Fmajor
b4-5 it's actually present in the Tenor D to G
4th as a succession of two notes will be part of a lot of leaps inside a chord (from fifth to fundamental) or common chord succession (circle of fifth, cadences etc...)
You won't found, however, both notes of a 4th between to voices attacked at the same time. 4th can appear in certain circumstances from passing notes and results from the incompletion of implied chords [A1].
Dissonnances will be aug4th dim5th, maj7, min7 (from memory I've never seen an interval above the octave in Baroque counterpoint or it would result from exeptionals circumstances). I'd say that, maybe not in Fux's rigorous counterpoint, aug5th is possible if resolved towards the interior of the interval [A2].
I hope it is helpful ☔