There is token to post original caption without hashtags,check the repost tool.Also option to post original caption without mentioned users.
If you want you can put your hashtags in the comments,just put your hashtags in the dynamic window and type [COMMENT] in the caption window,and next time you post your hashtags will apear in the first comment.
No, that won’t work. If you did that you will have original post caption without mentioned users + original post caption without hashtags and not original post caption without both.