Deacon, 24, will join for his second stint at Bower Fold, having previously joined the club in February 2017 from Fleetwood Town, making six appearances.
Barlow, 20, has featured prominently in pre-season so far for Celtic and now makes his move to the club official.
The centre-half is originally from Bury and was part of Crewe Alexandra’s youth setup before joining Kilmarnock in 2018. He spent two years in Scotland before making the move back home.
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