...
(a) You can define a maximum of 3 results
(b) Optional Plugin /or Add-on available (may require purchase)
(c) You can link On-Screen Takeoff Condition Results to Excel
(d) One user can work in OST and another other on the QB side, but not at the same time
(e) See Backup your PlanSwift Jobs for details
(f) See OST/QB Can I Use "Cloud" Storage? or PlanSwift - Storing Your Jobs on a Network Drive for details