Since your question is made up of multiple sub-questions, I would like to go step by step, answering each of them separately.

1- The 1928 Alphabet reform was certainly not the first attempt to write Turkish in the Latin alphabet. Here and there, Ottoman Turkish was sometimes written in the French Latin alphabet. A good example of this is the train stations from the late 19th century Ottoman Empire. These were typically owned and built by foreign companies. But still, they are examples of Turkish written in Latin before 1928. Here you can see one example from modern-day Susurluk, known back then as Su Sıgirlik in Ottoman Turkish. You can see it is treated as though it were a French word: Sou-Sighirlik. Another example is from the Balikesir station, written in a similar manner in both French Latin and Ottoman Turkish. This was not limited to train stations, of course. Shops also had signs with similar experiments. Typically, these were intended for Westerners in the Ottoman Empire rather than for Ottoman citizens themselves.

Moreover, there were some proposals to drop the Arabic script and adopt the Latin script. So far as we know, these go back to mid to late 19th century when an Azerbaijani intellectual, Ahundzade (Ahundov) Mirza Feth Ali made such a proposal. There were others arguing for this view in the early 20th century too. These are made sometimes in very subtle ways. Ictihad, the flagship journal of the radical Westernisers in the Ottoman Empire, for example, used Latin rather than traditional Arabic letters (1, 2, 3... rather than their equivalents in modern Arabic script).

Finally, an honourable mention goes to the Baku Congress of Turcology in 1926, where Turcologists from all around the world (but mainly from Turkic lands, including some from Turkey) discussed the matter and ultimately decided that a Latin-based script would fit Turkic languages the best. This was two years before Turkey adopted its own Latin-based script. Considering the scientific background of those involved, though, I think it is fair to conclude that here their concern was less with the politics and cultural affairs relating to the alphabet question than the linguistic aspect. As will be evident below, the choice was not this simple for politicians or the general public.

However, we should not exaggerate. I think it is all too common a mistake jumping from the premise that there were some individuals thinking that to it was a common idea. It was not at all. More on that later.

2- Yes. Without additional training, a modern Turk can read as much Ottoman Turkish as the average American. But the alphabet is only the minor part of the issue. Much more of a problem is the fact that Turkish underwent a largely conscious purification process from the 1920s to our day. A significant portion of Arabic and Persian words were purged out of it, replaced by words derived from ancient Turkic or simply borrowed from European languages, mostly from French and more recently from English. Moreover, the high Ottoman often uses Persian noun phrases, Arabic plurals, repetitive adjectives... If you are familiar with Italian or French, the difference between Turkish and Persian noun phrases is roughly like this: in English, we say 'blonde girl's shoe'. In Italian, you would have to say 'la scarpa (the shoe) della (of the) ragazza (girl) bionda (blonde)'. The former is how Turkish does it, the latter how Persian and (sometimes) Ottoman Turkish does it. Modern Turkish no longer has noun phrases like the latter. The examples can be multiplied but what is key is that, yes, younger generations cannot read Ottoman Turkish without additional Turkish, but no, that is not even primarily because of the alphabet change. Various testimonies make it clear that younger generations (and much of the people who were illiterate and who used a Turkish closer to the modern one used today than to the written Ottoman) during the 20th century in the Ottoman Empire had trouble understanding older works, precisely because they did not understand their vocabulary.

3- There was some resistance, but it did not amount to much. You still see it in Turkey, with people deliberately trying to keep Ottoman Turkish alive either by educating younger people to read the old script and/or by deliberately using older, Arabic and Persian loanwords. This was the same in 1928. Though there was some resistance, it did not stop Ataturk (he was the one pushing for a rapid reform, despite advice and pleas from even many of their close friends and government figures) from implementing it. We know, however, that until 1928 the alphabet reform was a taboo. This is because the Arabic script was and, to a lesser extent, is considered not merely as such but as 'the Quran script'. This is why despite many arguments against it (such as göl, gül and kül written identically, but meaning lake, rose (as in flower), and ash), it was preserved. It was much more than a merely linguistic matter.

Speaking of the resistance from government figures, it should be noted that their resistance was typically more practical than ideological. I have in mind people like Ismet Inonu who did not want such a rapid shift, fearing its potential consequences both in terms of a popular reaction and rendering reading and communicating chaotic. Ataturk quite literally gave people about three months to learn the new alphabet and start using it.

4- I do not ever recall seeing anyone argue that the Arabic script was more efficient in writing Turkish than the current alphabet. But since efficiency is not the issue here, you do have people advocating for more widespread Ottoman Turkish education. But, as before, these people do not really advocate for dropping the Latin script. They say children should learn the old alphabet as well as the new one, and more commonly, they use and encourage the use of older words.

For further information in English, you might want to check Geoffrey Lewis' book The Turkish Language Reform: A Catastrophic Success.