The list is going to take a while to check so I'm going to update this post irregularly.
Like I wrote, several comments are just "oh, nostalgic...". You can't say from them they did 100% or just participated, but the way they write anecdotes make it more likely (I'm afraid translating the whole thing 1:1 would be too time consuming a beyond my abilities). I'll write the impression the comments give me.
1 Doesn't say, from they way he writes seems likely.
2 Same
3 Doesn't seem like it.
5 Doesn't say, but Umeno/Matano (same person) is the only composer of Parodius, so yes.
13 Doesn't say, from they way he writes seems likely.
18 He says he wasn't officially in charge so his name isn't in the staff roll, but did several songs. In a OSV interview he confirms it.
19 In
Goemon 2 liner notes Yamane confirms she did the ending (first song, intended to be stage music)
36 He thanks people for selecting this and also asks you to check Konamic Golf, so I suppose he did it.
38 / Happy ending: confirmed. He comments they asked him to write 6 songs in a week, maybe he did just 6.
38 / Bad ending: Confirmed
43 Doesn't remember too well but thinks he did stage 1 and the ending.
45 This is what he is saying, more or less
"Aarg, writting this song was such a pain. Just kidding! (dead expression)
The person who wrote this song was, with the same surname as me, Mr. "Fake Technouchi".
However he's not here anymore. Techno Banzai!"
A man called Shigehiro Takenouchi was credited in Metal Gear, that's probably the composer.
46 He thanks people for remembering this, comments Exciting Billard had an adult mood. Maybe he did it?
48 Seem he did it *recheck
50 Very likely. Also, "VAP上高" could be read as VAP Uetaka. In fact I think Uetaka a is more common reading.