Yes, I think so.
If I am in your position, I may buy 2 more muses01 and put them in LPF stage and the matter is settled once and for all for these 2 sections.
Many users who installed muses in HP/RCA buffers did not find much improvements. In fact, many found that 49710/49720s (metal caps) perform very well in HP section and I can vouch that wholeheartedly. I have never tested 49990 so can't comment.