Both could make their home debuts in the Yellows' Emirates FA Cup first qualifying round replay against Morpeth Town on Tuesday night, following their 2-2 draw in the last Saturday.
Mfuni, 18, was released by Preston North End in the summer, and played at Cantilever Park for Blackpool Under 23s in their pre-season friendly against the Yellows back in July.
He also spent time on loan in the Northern Premier League with Witton Albion last season, and has recently had trials with Football League clubs.
Hometown boy Walker, meanwhile, helped local rivals Warrington Rylands to promotion last season. His former clubs also include Matlock Town and Stalybridge Celtic.
Walker made his Yellows debut as a second half substitute during Saturday's 2-2 draw with Morpeth in Emirates FA Cup qualifying.
On the double signing, manager Mark Beesley said: “Teddy’s someone we’ve been interested in for about six weeks. It’s been a bit drawn-out but with us only having two centre-halves, we wanted another one to put pressure on them.
"I’m thankful we’ve been able to get that one over the line.
“Dec became available in the middle of last week and we saw it as a good opportunity to bring a good player and character into our squad.
“He can play a variety of positions, he’s a local lad and a good player. To bring someone in of his calibre will only enhance the squad.”
Photo credit: Warrington Rylands
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