NATO is not yet dead beat and they want to hand Russia yet another birdie by denying them a Mediterranean naval base in Tartarus just like they did in Libya. That will leave Russia sucking its toes in the Black Sea with effective mechanisms to curb the movement of their ships with the cooperation of Turkey. Plus if they have real fears about Iran launching missiles at them, they want to deny Iran easy access to Lebanon.
Pakistan will still do nothing openly. Just like they have been fighting us on the sly, they might send weaponry and some brainwashed towel heads to wage another Jihad against Israel. China will opportunistically jump to sell weapons to Iran, Syria via the Pakis in return for oil.
And except for a few MLRSs Syria doesnt buy crap from China. Most of their military is Soviet/Russian origin. And Iranian army uses old shitty Chinese Type-59/69 tanks, some new Chinese IFVs and the airforce uses a couple dozen crappy Chinese F-7s. Not very likely they have any J-10s or JF-17s. Those Chinese weapons wont last for more then an hour in a fight against Israel. The only thing of concern are the surface to surface missile (probably with nukes) and the cruise missiles. Syria/Iran's conventional military strength is worth nothing. Israel has beaten 6 Arab heavyweights single handedly. And Iran couldn't even win against Iraq when they had American F-14s,F-5/F-4 Phantoms. Back then they had a better airforce then even Pakistan! Today half their fleet is grounded.