No. Animated films didn't get 70mm blowups. The film was 35mm only, Dolby Stereo only. The mix heard on VHS, Beta, Laserdisc, and the HDTV broadcasts is the one and only original mix. The 5.1 remix was done by Universal about 10 years ago, with no input from Don Bluth or anyone involved with the production.

Perhaps the additional/alternate SFX and walla were alternate/unused stems from '86, like the additional off-screen dialogue and the alternate voices for the orphans. But whether they were new or just not utilized in the released mix back in '86, I must reiterate, they were not in the original, approved, released mix.

Sometimes it's additional effects or dialogue. Sometimes it's missing effects or dialogue. You may recall the 5.1 remix of Animal House, where for some reason Neidermeyer's "Now drop and give me 20!" is joined in progress, so it's just "--drop and give me 20!" Even if a 5.1 remix is made entirely from original stems, it needs to be meticulously checked against the original final mix.