We've already decided that Half Cold Half Hot only needs a picture. The gif doesn't add anything extra. Also please stop replacing images with slightly more compressed versions for no reason. They're already appropriate file size.
I don't see the harm in adding an aditional gif if it's to be consistent like other qirk pages. Also it would be good practice to reference/link the actual thread were the decision was already made. As for the file compression, I think it's a good measure because it does reduce loading times on pages if the files are smaller. One final thing I would like to address is that this user is both a VSTF and a highly experienced Fandom editor. It would be a good idea to sit down and listen to some of his suggestions. Just because our way "works", doesn't mean there's no room for improvement in how we do things.
If image load times are a concern, then wouldn't stills be preferred over gifs?
The still for Half-Cold Half-Hot illustrates the whole Quirk: ice comes from his right side and fire comes from his left side. More complicated Quirks, like Copy, do need gifs to illustrate their setups and effects.
Izuku redirects to Izuku Midoriya. If last-name redirects are unnecessary, then first name redirects should also be unnecessary. Also, being a Japanese show, it makes more sense to have the last names redirect to the article page than the first names...
Having redirects for the Japanese name order is something we should have, as some scanlators use that order. There was someone who was working on adding those, but I suppose they stopped.
Shortened name links are unnecessary though. Typing "Izuku" will bring you to "Izuku Midoriya" and if you're adding a link to an article, inclusion of the full name shouldn't be an issue. If it is an issue, shortening can be done in the article.
Redirects with just the family names are misguided. We have multiple Midoryias, Katsukis, Iidas, etc.
Yes. For these cases, you should make Disambiguation pages. I was actually thinking of doing that for Katsukis, Midoriyas, Jiros etc. but I did not find any existing disambiguation pages so I decided against it.
The search results page should not be the landing page for a search like "Midoriya". A "Midoriya" page with links to Midorya-related pages and things like family history would be useful. For characters who do not have families also named in the show, then their last name should redirect to their page.
Because it's not really an issue. [[Midoriya]] shouldn't be used in an article so it doesn't need to lead anywhere. Specifying which one in the article is the better option. Linking to a disambiguation page wouldn't clarify which character is being mentioned.
Plus, wikia suggests relevant articles as you type, both in the search bar and in articles.
This doesn't make any sense, as they are not commonly referred to by their first names in the series. Due to this, a reader is more likely to search for "Bakugo" than "Katsuki". What is the difficulty in your understanding of this?
In my opinion, "Last name First name" redirects are necessary because as Callofduty4 said, people tend to recognize the characters' last names more than their first names. The most important thing about redirects is you get what you want automatically from the search bar, as the result sole family/first name redirect is completely unnecessary because yeah, you don't need to make an "Izuku" redirect for "Izuku Midoriya" because his name will automatically pop out. To summarize it:
"Midoriya Izuku" redirect for "Izuku Midoriya" ✓
"Izuku" or "Midoriya" redirect for "Izuku Midoriya" ❌
For the disambiguation, I don't think it's necessary. I handle a wiki where characters share their first/last names with the Japanese voice actors page and it's completely fine to leave it like that without disambiguation page. Well, that's just my opinion.