The bodies of the Goddesses can be reassembled but it takes some time. Ludociel and the others will leave the bodies of their hosts without trouble them.
Another Goddess of the same rank as Nerobasta. So even Lance Corporals can qualify as High-ranked Goddesses.
Maybe Nakaba redefined the ranking in the story cause he likes the wording(or he doesn't know it all that well)
Wait that goddess said that she told Ellizabeth to "break up " with Meliodas. Does that mean that Meliodas and Elizabeth were "dating" at that time ( in the middle of a war)? I don't know I'm a little confused maybe she meant it as " stay away from him " or something. Because I don't think they were literally in a relationship maybe just in love but not that " official" with all that holy war thing going on
They were a canon couple, even Ludociel was asking her to "dump" Mel because there were "more appropriate partners" for her in the GC(he was trying to insinuate himself, by the way he invaded her personal space and lifted her chin and the way Nerobusty was blushing while looking at them

). What's so strange about people being romantically involved during a war, feelings don't catch a break in times of conflict, on the contrary. History is rife with relationships built during wars, weddings even, or even births. And there would be nothing so intense to piss the parents off so badly as to come to Britannia themselves to punish the kids like the kids making it official.
That apparently doesn't matter as Zeldris had Gowther's Commandment all this time and still considered Fraudrin a member of the Commandments.
As
@baditz said, it makes it worse, he granted 2 actual decrees to Gloxinia and Drolle(strangers to the clan), but he kept Gowther's away from a demon general in Melascula and Galand's power range. And the guy really made an effort to help out the clan. Unlike the wishy-washy guests of honour in the DC.