Thwaites, 18, is regarded as one of the best set-piece takers in English youth football and was named in Carrick's Premier League squad for the first time for the away fixture at Chelsea earlier this month. Carrick said the call-up reflected his performances during a training camp in Ireland. He has since become a regular presence in senior training at Carrington.
Devaney, also 18 and previously the club's under-21 captain, accepted a loan move to St Mirren in January and has started eight of a possible ten Scottish Premiership games for the relegation-threatened side. The Ireland youth international has drawn strong reviews from fans and staff since arriving in the winter window.
Both would benefit significantly if Carrick remains as head coach, with academy specialist Travis Binnion part of his backroom staff providing a direct developmental bridge from youth level.
United are targeting two senior midfielders in the summer window, with Atalanta's Ederson, Sandro Tonali, and Nottingham Forest's Elliot Anderson among those on a condensed shortlist reported by The Sun.
But the prospect of Champions League football and deeper cup runs next season creates space for Thwaites and Devaney to accumulate first-team minutes alongside senior arrivals.
United chose Thwaites for a sit-down interview with under-18 captain Dan Armer last week — an unusual move for a club that typically limits academy media exposure — a signal of the regard in which he is held internally.