Moura enjoyed a good pre-season with Spurs and started their 2-1 win over Newcastle United on the opening weekend of the Premier League campaign.
The Brazil international failed to make much of an impact, however, and he still has just one league assist and no goals since joining from Paris Saint-Germain in January.
Mario, meanwhile, spent the second half of last season on loan with West Ham United and appears to be edging closer to the San Siro exit.
Asked about Betis's interest in the pair, Ferrer told El Desmarque: "They are two great footballers and if we have possibilities we would like to have them. But we have to be realistic and know what we can do.
"We try to distribute the economic potential well in order to try to reinforce and improve the workforce. We have made six additions, replacing players that last year performed very well, with a brilliant goal, and we think we have improved. It will be difficult to match what we did last year."
Betis finished sixth in La Liga last season to earn a place in the Europa League.