Sanders and Ward are obviously both good players, but they aren't making huge $. Vernon and Tru are young guys at premium positions hitting FA at the perfect time. Both are going to get Paid(yes, with a P). Howard will probably get at least Crawford type $ too. I'm not saying we can't sign multiple pieces, but the 4 guys OP listed is probably bordering on adding an additional average salary per year of $35-40M total.
Just using comps from last free agency...
Howard = Odrick- 5 years 42.5M
Vernon= Jerry Hughes- 5 years 45M
Tru Johnson= Maxwell (? maybe not quite, but I think he'll be close)- 6 years 63M
Trevathan= David Harris- 3 years 21.5M
The Denver Broncos signed WR Emmanuel Sanders to a three year $15 million contract on March 17, 2014. Sanders received $6 million in full guarantees which are made up of a $3 million signing bonus, $2 million 2014 base salary, and $1 million roster bonus. Base salaries of the contract are $2,000,000(2014), $4,000,000(@015), and $5,000,000(2016).
DeMarcus Ware signed a three year, $30 million contract with the Denver Broncos on March 12, 2014. Ware received $16.5 million in fully guarantees. The fully guaranteed portion of the contract is made up of a $5 million signing bonus, $5 million roster bonus, $3 million in 2014 base salary and $3.5 million in 2015 base salary. If Ware is on the Broncos roster on the 5th day of the 2015 League Year he will earn an additional $3.5 million salary guarantee.Ware has a $3 million roster bonus due on the 5th day of the 2016 League Year.
TJ Ward signed a four year $22.5 million contract with the Denver Broncos on March 11, 2014. Ward received a $5 million signing bonus and fully guaranteed $ 2 million base salary in 2014. His $4 million salary in 2015 is guaranteed for injury only and becomes fully guaranteed on the fifth day of the League Year. Base salaries of the contract are $2,000,000(2014), $4,000,000(2015), $4,500,000(2016), and $4,500,000(2017).
CB Aqib Talib signed a six year, $57 million contract with the Denver Broncos on March 12, 2014. Talib received $11.5 million in fully guaranteed salary. The full guarantee is made up of a $5 million signing bonus, $2 million 2014 roster bonus, and $4.5 million 2014 base salary. His 2015 and 2016 base salaries are both guaranteed for injury only and will become fully guaranteed if he is on the roster on the 3rd day of that respective league year. He has $500,000 roster bonuses paid for games active in the first three years of the contract. Base salaries are $4,500,000(2014), $5,500,000(2015), $8,500,000(2016), $11,000,000(2017), $11,000,000(2018), and $8,000,000(2019).
First year cap #'s
DeMarcus Ware - $9.66M
Aqib Talib - $7.968M
Emmanuel Sanders - $4M
T.J. Ward - $3.25M
All doable you just have to have a Front Office who is aggressive, competent, and willing to make the kind of moves that make/keep you a Super Bowl contender. While I wouldn't want the 4 FA's the OP mentioned, I wouldn't agree that they would be more expensive than the 4 marquee free agents Denver signed on 2014. You can't waste time or cap space on JAG's like Jasper Brinkley, Andrew Gachkar, and Mackenzy Bernadeau. Not if you are serious about winning a Super Bowl before Romo's and Witten's time is up.