Yes. Malwarebytes is not a traditional antivirus or antispyware program. The free version (with on demand scanning, no real time scanning) is pretty much all you need. From the Malwarebytes info page: Works Well With Others - Cooperative functionality.
Yes you can. Malwarebytes has been specifically written to operate alongside more traditional anti-virus products such that they do not 'interfere' with one another. All the major anti-virus products have been catered for, including MSE, Avast, Kaspersky, Norton and so-on-and-so-forth.
1*Samsung 840 EVO 120GB SSD;
1*OCZ Vertex 2 60GB SSD;
2*Samsung F3 SpinPoint 1TB in RAID0;
1*Samsung F1 SpinPoint 1TB;
2*Western Digital 1TB External USB 3.0
1*Western Digital 500GB External USB 3.0
1*Seagate 500GB External USB 2.0
PSU
Thermaltake ToughPower QFan 750W
Case
Thermaltake Element S VK60001W2Z
Cooling
Corsair H60 Water Cooling, 2*230mm and 2*80mm case fans