Is it necessary to replace the monster hunter world novice alpha suit with the dragon-killing suit?

If you're talking about the defense team or the suit of armor you sent, it's not necessary. This equipment is a novice life-saving equipment, which can be used until the end of the main line. M-position land reclamation has good graduation armor in the upper position, but if you are too lazy to kill time in the upper position, then the armor of M-position land reclamation defense team can also be used.