So far as I know
बहु can be used only as क्रियाविशेषण as exemplified by you and not as a qualifying word for another विशेषण as in this sentence अयं बहुः सुन्दरो बालः। In case this happens, then
बहुः can also be compounded with the word सुन्दरः and the form would be बहुसुन्दरः which means "less beautiful" as in the case of बहुपटुः which means "little less skilled." (See Kashika on the aphorism 5.3.68). To explain, the taddhita suffix बहुच् is used at the beginning of the word to which it is added. The aphorism विभाषा सुपो बहुच् पुरस्तात् (अष्टाध्यायी 5.3.68) which means "The taddhita affix bahuc optionally occurs before (purastaat), and not after, a nominal stem which ends in sup and has its meaning qualified by "less"(ईषदसमाप्ति). Even when we use बहु with मान्य, बहु मन्यते इति बहुमान्यः which looks as if this word were used as a qualifying word for मान्य but this kridanta word
मान्य is formed by the kridanta suffix ऋहलोर्ण्यत् (
अष्टाध्यायी 3.1.124). It is obviously in the sense of kriyavisheshana. This sense is commonly observed in Sanskrit language, e.g. Kullukabhatta on Manu 2.117 says आध्यात्मिकं ब्रह्मज्ञानं यस्मात्तु गृह्णाति ते बहुमान्यमध्ये स्थितं प्रथममभिवादयेत्। A person should pay his obeisance to the person, sitting among the highly esteemed persons, from whom he receives the knowledge of Brahman.
If you come across the use of bahu with another qualifying word, please let me know so that we may deliberate on such a linguistic usage.
The rest later on on hearing from your side.
Kanshiram
Retired Associate Professor
Hans Raj College.