Aleix: /əˈleʃ/ in eastern dialects, /aˈlejʃ/ in the western ones/valencian.
Andreu: /ənˈdɾew/ in eastern dialects, /anˈdɾew/ in the western ones.
Both with /e/, as every(?) word ending in -eix and -eu.
In the thread Pronunciation: the surname "Deulofeu", it was said that "-eu (hereu, europeu, museu) is more often pronounced with an open e than with a closed one." (#2) and "Also in central Catalan they tend to pronounce all -eu endings like [-ɛw] even in cases when the traditional pronunciation is [-ew]. " (#6)
Yes, that's why I put the interrogation, I wasn't sure if it was the case for "every" word (it's not).
As you correctly say, there are some exceptions, words ending in -eu always pronounced as [-ɛw] (the ones you put, hereu, europeu...) but most of them (greu, breu, meu, teu, seu...) are with a "closed e" ([e]).
For the verbal desinence in -eu: voldreu, sabeu, direu, diríeu..., it varies on the dialect ([-ɛw] in Central catalan, [-ew] in some other places).
I suppose these "more often" with one or another depends on which dialect and which words we consider (it's almost always [-ew] in mine).