[Q]Obviously, the ideal would be a load calc done but with already pursuing three bids and none of them even mentioning a load calc, I'm guessing the reality of finding someone that thorough is difficult, especially since with no AC currently, time of of the essence.
With 130 S.F. of glass (8 windows or less),
2-Ton is adequate for 1,140 S.F. residences
(<~10 years .. good windows, R-19 wall, R-30 ceiling) with basement in St. Louis.
Basement cooling load is likely <~20% of the total,
if there are no exposed basement walls or windows.
Air distribution may more of a concern than whether you wish to install a 2-ton or a larger 2-stage unit if Your thermostat set-point is < 75'F.
Is the cost difference for Variable Speed air handler
(> humidity control) important?
V.S. AHU also provides somewhat of a band-aid for an under-performing air distribution system.
I am sure many contractors would perform a load calc,
if one provided ~$1oo cash up front. Load analysis would take < half-hour for a 7-rooms residence if you provided all the details.