Regarding the shape of the family by the end of season 6, I’d chart it like this:

Tony Soprano (Boss) [possibly still technically acting boss if DiMeo retained his title in name only]
Silvio Dante (Consigliere) [comatose]
Paulie Gualtieri (Capo) [running what’s left of the merged Soprano/ Gualtieri, Altieri/ Gervasi, Aprile/ Cifaretto and Moltisanti crews]
[Barese crew and Junior crew vacant if not disbanded]
Benito Fazio (Soldier) [99.9% likely made between seasons 5 and 6]
Pat Parisi (Soldier) [passed over for promotion again at the end of season 6]
Beppy Scerbo (Soldier) [still active and delivering tribute to Junior in season 6]
Albert Barese (Soldier) [likely still around]
Walden Belfiore (possible Soldier) [if made during the show, it was likely between seasons with Benny]
Tony Maffei (possible Soldier) [seen delivering tribute to Tony after Bobby’s murder; either made before 1999 or between seasons with Benny]
[Several incarcerated or otherwise inactive soldiers]

There is a sense that the family is depleted by the end, encapsulated by the wide shot of Paulie sitting outside Satriale's completely alone. 16 confirmed members either died or were killed throughout the show, Junior got shelved, Murf Lupo and Tommy DiPalma were too old and senile to be trusted with any criminal activity anymore, Pat Blundetto was retired, Sil was comatose, Feech, Larry and Beppy Sasso were in prison, Carlo flipped and there were who knows how many other members jailed with Ercole DiMeo or who followed the older guys into retirement.
Due to this attrition over the course of the show, it's conceivable that the DiMeo family was down to about 10 or fewer active members at the end of season 6 (there is precedent for that with Philadelphia estimated to be down to 10 active members on the street by 2004).
The absent-since-season-4 Allie Barese is most likely still around but it's notable that the Barese crew had no impact on the show or presence at family gatherings since Larry's incarceration and turning CI. Tony and Paulie were happy that Larry blamed Willie Overall solely on Jackie but they weren't coaching him on what to tell the feds and they weren't in contact so I very much doubt that they left him as a capo.
The problem with a lot of this theorising is it's hindered by the focus of the show as a piece of drama and the technical makings of a TV show. We can't chart all the old extras Junior hung around with throughout the show and count them as members because then his crew would be the size of half the family. The real reason Larry came back and Allie disappeared was because of behind the scenes troubles, not plot lines.
We also can't rely on wiki sources for information. A lot of the time it seems a general lack of understanding of LCN leaves characters listed as soldiers when they clearly aren’t. A lot of wikipedia articles seem to be likely written by people who conflate 'making your bones' with getting made. Even some official books misuse the term soldier to describe associates like Little Paulie and Donny K (who were definitely not made members because of the way they were repeatedly beaten up without consequence). People often invoke Benny being beaten up as evidence that he couldn't have been made but he seems to be the exception; Artie got a pass as a civilian and a close friend of Tony (Al D'Arco said he was recommended to stay an associate so that if he ever laid his hands on a made guy he could say he just didn't know), and Benny lost his dispute because he was doing the scam off-record.
Regarding the status of the Junior and Barese crews, crews have been left without leadership for long periods during the show. On the FBI chart from season 3, the Altieri crew's capo slot was seen to still be vacant (and with Ray Curto as an enthusiastic informant at the time I doubt the FBI would have failed to identify any hierarchy members). Bobby was still only running the Junior crew as a high-ranking soldier by the start of season 6. With the attrition in membership, I think it’s more likely that the crews were merged.