What a wonderful goal you are setting yourself! I congratulate you and wish you every success.
My goal has some parallels, namely, I want to try and get my Hokkien to a level where I can function comfortably in it - at least for basic conversation (which is not the case at the moment, mostly because of the huge number of words that I don't know).
But this is a longer term goal for me. For me, mastering basic Mandarin is more important, at the moment. [A statement which might get me banned from this Forum .] But along the way, new characters I learn in Mandarin do throw light on Hokkien, so this contributes to that other goal as well.
All 3 of your points appeal to me a lot.
I have done something slightly similar with my parents and uncles and aunts (all in their late 70's and early 80's nowadays), except that the emphasis in my "research" was less on the language itself, and more on the actual events and conditions of their lives, when they were young in the 1930's to 1960's. But in that process, the way they speak has also of course been recorded.1. Record (voice) words spoken in daily life by older generation.
This one particularly strikes a chord with me. As I've said a number of times on this Forum, I *cringe* when I see the "subtitling" under many Hokkien (karaoke) songs, where they use pinyin "b-" and "g-" for POJ "p-" and "k-". I really can't understand how the people who use this system don't see that if one does this, then there's no letter that can be used for the POJ "b-" and "g-"! That people from outside of Malaysia/Singapore might do this is to a certain extent understandable (they have few other models than pinyin), but that people in Malaysia/Singapore do it is (IMHO) totally unreasonable, when they have a perfectly adequate example of Malay/Indonesian, where the (POJ) letters "b-" and "g-", and "p-" and "k-" (and "t-" too) correspond very much to the Malay ones, and only the ""ph-", "th-", "kh-" need to be added for Hokkien.2. Document them with proper romanisation - to start educating younger generation.
I like the compromise position on this. I agree that one should strive to find and use pun-ji where possible, but in many cases, it's just too obscure to work out, and one can spend hours and hours arguing about which character to use, whereas it's much more important to just choose one and try and get everyone to use it.3. Look up for the right or reasonable characters, may not be pun-ji.
Do you know "the other Sim", who studies at SOAS in London? Andrew knows him too, and I think his goals (and dedication) are very similar to yours.
PS. Don't you people think that the current flood of spam here is really weird? It's not even advertising products, but appears to be incoherent fragments of English mixed with utter nonsense.