If I were the Soviets, I'd choose Option 3.
WP usually have more units, and if you bunch up your forces too much you get blasted by artillery and airstrikes. Furthermore, NATO quality superiority is usually a given, so by focusing on a single attack vector allows NATO to set up a killzone that can decimate your forces while you are unable to leverage your numbers.
There is also another factor in favor of a push north of Melle: the high hill there is a superb spotting and sniping place. I'd do my best to set up shop there with some scout unit and maybe some AD and ATGM. From there you can both rain fire on the town and on the whole middle-northern part of the map.
In the south there is another geographical feature of some importance: the southeastern hill from which you can fire on everything that tries to cross the river and the town of Schlachten. I'd surely try to sneak a unit (maybe an expendable Mech Infantry one) there by hugging the southern edge of the central hill, then run toward Schlachten and set up a reverse slope defense there.
This way you will force NATO to spread up its forces, and you should still have some reserve with which exploit the most favorable front, as per Soviet doctrine. Probably it will end up joining the very, very likely melee in Melle, but a Tank Company or two could tip the scales at Schlachten or north of Melle, allowing for an armored offensive in NATO backfield.
I always try to reach the NATO backfield and hunt their guns because I'm very very wary of their artillery: their command cycle is so fast they usually fire twice as many times as my artillery, and counterbattery fire never seems to work for me...
Now, the WP helos... I don't know. I'm always conflicted about their use: if you send them forward, NATO can take some early casualities and slow its advance, giving you time to move forward and snatch some strategic position. Waiting for the enemy from prepared defenses and ambush position is a potentially game-winning strategy. This tactic, however, almost guarantees you will lose your helos early, so no "flying reserve" if the enemy manages to surprise you during the middle-late game...