I don't know how the chain adjuster is configured on the 1198, but I believe Motowheels has the spanner for sale. There are many local 1098/1198 guys that can help you on that aspect.
I'm sure the oil change procedure/tools/parts are the same since the first Desmoquattro, except for the pre oil screen. You need a crush washer for the oil drain plug. 10mm hex to remove oil drain plug and 11Nm (8 ft lb) torque to replace it. I'm sure your motor is a deep sump type like mine. It requires a 5mm allen wench to remove the small drain plug on the left side, next to the oil screen plug/sump. Then loosen each of the four oil-screen bolts with a 5mm allen wrench. Pull off the cover and the gasket, reach up and pull it out. A rubber seal will come out too. When putting the cover back in make sure the rubber coated gasket is in position and properly seated. Those deep sump 5mm bolts are torqued at 10Nm (7 ft. lb.).
To remove the oil filter, I simply use channel locks on the filter and unscrew it. I then fill up the new filter to about 3/4 with fresh oil, coat the gasket with some oil then spin it back on hand tight.
Filling seems to be the only touch and go time I've had with any Ducati. The best way to judge exact oil levels in the site glass is by sitting on the bike and balancing it straight up. Have someone tell you where the level is, maybe even mark the level with a sharpie. I then set the bike up on both my stands and wait until the oil level settles down. This gives me a close idea of true level for refilling by comparing the mark with the actual level while on the stands. BTW, I usually warm up my bike prior to changing the oil, per recommendations by many.
I fill the crankcase to about 3/4 full and then start the bike for a few seconds then shut it down. It takes awhile for the oil to settle back down in the site glass, making this part of the process slow going. At that time I play cat and mouse with the site glass, because sometimes all of a sudden it will fill without coming back down. At that point you know the crankcase is full. Up until that point the bike acts like a bottomless pit when it comes to filling the site glass. Seems to me I use around 4 quarts of Amsoil from Galaxy (Jon) to get it done. When nearing the end of the filling process just pour in very little oil at a time. I usually fill it to just below the max mark.