I've been doing this for many years and there are only a tiny few of us, beyond professional document examiners, who might care enough to delve into these questions.
A few things to consider:
You're more likely to find solid advice from typeface historians than you are SCM historians. You're also likely to find better advice on this topic in the more specialized fora like https://typewriter.boardhost.com/ or the typewriter discord https://discord.gg/UzaREHJnX
You're better off using the exemplars from the catalogs (several .pdfs in the TWdb when you're logged in, or on munk.org in scanned photo format). The photos and identifications in the individual galleries of the database are USER IDENTIFIED and aren't always the most consistent as a result. Knowing some of the bigger, more knowledgeable collectors on the database and who knows what best or who has studied areas the most is incredibly helpful here. (Several of your examples are via James Grooms, who is a significant collector and generally does solid identifications, provides photos of slugs and foundry marks, but still often asks for confirmations of typeface identifications in the various fora.)
The foundry marks on the numerals for most machines are very often are different from those of the alphabet so you may find that particular machines used something like Pica No. 1 for the letters but something different, but potentially close for the numbers.
The slugs and designs for the number one are often the least reliable over time as it was often left off of machines entirely until the 60s or 70s. Even when a foundry specifically designed this numeral, many manufacturers left it off their machines though they often put an exemplar for it into their catalogs. Thus when you compare, you may be comparing the lowercase letter "L" in exemplars for individual machines. In particular, I've seen examples recently for Royal who had the number 1 in their catalogs, but almost never had a key on the machine for it and either relied on the user using the "L" or in cases of double gothic faces the letter "I", and as a result, you'll never find an exact "match" between the two.
An exact determination is highly unlikely to change the value of your particular machine in the slightest.
It would be nice if the Typewriter Database encouraged people to upload photos of their slugs and foundry marks specifically and had data fields for identifying the typefaces as well as fields for which sources they used to provide those identifications.
The level of resources and knowledge in this area means that it's incumbent on you to do your own research and come to your own conclusions based on what is broadly available in terms of original catalogs and exemplars in the wild. This being said, the only way the state of the art changes is for people who do this sort of research to publish it with their lines of reasoning on their own websites, here on Reddit, or other typewriter related fora.
Reply to u/frankinreddit at https://old.reddit.com/r/typewriters/comments/1sskes0/smithcorona_id_help_are_these_actually_pica_no_1/