Veltman and Lallana both came from Champions League sides.You can ask that question of players being released by any Champions League sides.
It's an irrelevant question if their wages would break your clubs financial structure.
Each of the players you have listed are likely to be on higher wages than Brighton's best paid player, so the answer is no, I wouldn't take any of them and wreck the harmony and financial health of the club.
If money wasn't a factor, I would consider Mason Mount to sit on the bench as a possible future Pascal Gross replacement.
You can leave the other transfers for West Ham, Villa, Everton and Palace to make yet more expensive mistakes.
Maybe some of them want to stay and the area... and not play for Palace.
Think the squad will get one or two established additions in the summer.