You could carry a couple of 12.7mm/.50 cal machineguns below-deck, and mount them above-deck on as-needed basis. Normally a missile FAC is not intended to be a coast guard gun boat anyway.
I think if they can fit an AK-630 gun mount plus under-deck ammuniton magazine on it, they should be able to use 2-meter long SAMs in VLS config.
The Israeli Barak, British Sea Wolf, and French Mistral SAM are all approx. 2 meters in length. Those can prolly go into a VLS system. Please see this pic for missile size:
And this pic for a typical 8-cel Barak VLS system size on deck:
The Crotale/HQ-7 and USN RAM missiles are approx. 2.8-2.9 meters long. These are prolly better installed on a turret, unless if we want a taller VLS above-deck structure.
I'm not sure if an 8-cel HQ-7 on turret would be too large, in physical size and interfere with the SSM's on the 022. If so we might have to settle with a smaller, 4-cel turret in its place.
The Russians have a lightweight ADGMS system called the Palma. Each combat module has 2 x 30mm AO-18KD CIWS guns and 2x4 Sosna-R laser-guided missiles. The SAM can engage targets up to 8km distance, and the whole combat module, included ammunition (but excluding radar) weights 6,900 kg:
This lightweight ADGMS system was shown in 1997 international sea power expo at Lima. However so far I don't think they have any export customers for the system.