I believe signing both and NOT signing Soler keeps them under the CBT. They are currently projected to be 52M under the CBT per Spotrac and 45M per Cots including arb raises. @redsoxpayroll thinks it would put them over the CBT as they are highest at projecting the current Sox payroll at 201M.
Personally, I believe the actually Sox budget is NOT the CBT, but lower.