[DCBryan1]

1. I would have to see proof of “some soldiers walked into a hanger and took off their patches and uniforms, changed into new attire and started working for various contractors with a “wink and a nod” from Russia.” Russia is a professional army and you just don’t give up highly technical and professional solders that cost a fortune in training with a “wink and a nod.”

First, Russians are whores, like the French, but less civilized. They go where the money is. Their pay and their standard of living SUCKS....and abuse by superiors and alcohol use is high. Secondly, since you and I aren't going to go on a sight seeing trip to Syria anytime soon, we have to look at recent Russian "professional" troops:

Exhibit A:

Possible Russian "professional troops" in civilian clothing acting as Pro-Russian "rebels" in Crimea:

Exhibit B: Multiple sources with google search "Russian Mercenaries" or "Putin's private army/armies" and you'll see non-state actions from Chechnya, Moldava, Eastern Ukraine, Crimea, Georgia/Armenia, South Ossetia, Libya, and especially Syria.

Russia’s Secret Mercenaries Fighting In Syria
Syria's Secret Russian Mercenaries

Russian mercenaries in the Donbass [to supplement pay]
Moldava sentences 150 for fighting as mercs in Ukraine [and elsewhere]
Russian mercenaries sign up for work in Syria
Meet the European fighters who have signed up to fight in the Ukraine [and Syria]

Anyways, you get the idea.

2. Firing mortars or arty accurately in “indirect fire” mode is not easy. ISIS never got the hang of it (all their pics of their capture artillery is in direct “flat” projectile mode when used in combat.

Wrong. 2S4 has guided round and is VERY accurate. IIRC from our WIC (Weapons intelligence course) at DIA, Russians are using the The latest modern munitions "Daredevil" system. They have direct line of sight laser targeting or a remote laser target detonator (1D15) and some satellite/cell/RF syncro equipment to increase their accuracy, have their targets “illuminated” by a laser beam in the later stages of flight (mortar rounds are lobbed in slow and usually don't come in screaming like conventional arty).

It is even harder with bigger projectiles over longer distances. Calling in a IDF strike would most likely get the observer killed if the guy on the “other end” doesn’t barely knows what he is doing.

They know what they are doing. They have LOTS of experience in the regions mentioned above.

[NorseViking]

Daredevil is like a 1980s vintage. Originally used in Afghanistan by Communist forces to supplement LGB in areas with higher manpad threat to aircraft where they had enough command to move heavy equipment on the ground. It proved to be more effective than expected.