I am about to install a minisplit in the basement. I have had a energy audit done on the whole house and at the time the lady said the smallest minisplit I can get should be sufficient for the basement. That would be around a 9k BTU model. I also had a load calc (IDK if it was done correctly because I have already been told that it had some discrepancies).  The load calc for the basment:
Component Btuh/ft2      Btuh          % of load
Walls                  10.0        7039         62.6
Glazing            28.2           56              0.5
Doors                 19.3         618             5.5
Ceilings                 0           0                0
Floors                  2.6         1329           11.8
Infiltration         3.0         2202           19.6
Ducts                                      0             0
Piping                                     0              0
Humidification                    0               0
Ventilation                            0                0
Adjustments                                           0
Total                                  11244              100.0
Cooling

Walls

Glazing Doors
Floors
Infiltration
Internal Gains

Component                   Btuh/ft2             Btuh          % of load
Walls                                    3.6                   2551           44.7
Glazing                                 93.3                 187             3.3
Doors                                     10.5                338             5.9
Ceilings                                   0                    0                   0
Floors                                   0.8                  395                6.9
Infiltration                          0.5                   344                6.0
Ducts                                                               0                    0
Ventilation                                                     0                     0
Internal gains                                              1890                33.1
Blower                                                              0                     0
Adjustments                                                                           0
Total                                                              5704                100.0

I want to know if the minisplit I was quoted with work good. Whats the modulation rate of this thing at say 55F outside? 
The basement is around 500sqft with a short hall and closet leading to a 130sqft laundry. So the layout out as your coming down the stairs is about 500sqft to the right and behind. Then going left is the hall going back along the steps to the laundry room. ENTIRE sqft is 600. No insulation that I can seein the outside walls. Ceilings 7.5′ with 2′ above grade.  I have sealed the rim joints. The basement is adjancent to a garage by about a 28′ wall. The garage is unheated. The wall in insulated by R11 I believe which maybe upgraded. We may turn the garage into living space at some point but unsure right now. I live in zipcode 24012. House was built in 1972. Basement has 1 window thats original.

The minisplit that I was quoted for is a Daikin model FTXB09 indoor ductless head with an outdoor inverter heatpump 17seer and a 9 hspf.  I think I have other option but will this work?  Im also planning to install a HPWH and That may put more load on the minisplit for this space as the laundry room is open. If the HPWH is too loud then I will have to close that room off and do some sound proofing.

Also does this heat load calc sound correct?  Im more concerned with heating the space than cooling.