I don't know if the team looks at it like that. They essentially tendered all three of them second-round offers, although Spears was original pick (which was the first round).
I don't think Dallas did that expecting to lose any of them, but just preparing to get something in case it happens. The Cowboys used the system that's in place which allows them time to work out long-term contracts if they want, get guaranteed service from good players for a year while they continue to try to get better at the position or get guaranteed compensation.
Reading into it that Dallas is preparing to lose Spears and develop his replacements by tendering all three just isn't justified. Of course, I'm not sure that's what you meant.