I've dug up a bit more information about Tanne Ost that I want to share:
1) The German forces had a "radar unit" already on the island as part of the defences. Removing this unit as part of the retreat from Finland was the ruse the Germans used to move the enitre first landing wave into/next to the harbour without being fired upon. It appears that this unit was not a "radar" unit per se, but rather an "acoustic radar" or sound detector unit, probably equipped with RRH acoustic listening station(s). A statement about the 1944 bombing of Helsinki says that the bombing force was first detected by the soudnlistening post on Suursaari, which alerted the Freya radars in Talliin and Helsinki to watch for the bombers. DOES ANYONE KNOW THE OOB/TO&E FOR SUCH A UNIT? Or even the designation?
2) The 1st R-Boat Flotilla appears to have had the following vessels assigned to it at this point: R-29, R-67, R-68, R-69, R-72, R-76, R-119, R-120, R-127, R-145, R-249. R-29 was lost in the battle. These were shallow-water minesweepers.
3) The 5th S-Boat Flotilla appears to have had the following vessels assigned to it at this point: S-85, S-110, S-116, S-120. These were motor-torpedo boats and were presumably the fleet's primary defence against the Russians (who were operating submarines and motor gunboats/torpedo boats in the area).
4) The 3rd and 25th M-Boat Flotillas appear to have had the following ships assigned to them at this point: M-14 (or M-16), M-15, M-17, M-18, M-19, M-22, M-29, M-30, M-443, M-453, M-460. These were larger minesweepers which could provide some offensive firepower (1 or 2 105mm deck guns) as well as providing safe passage through and around the large minefields.
5) The 7th Artillerie-Trager Flotilla appears to have had the following ships assigned to it at this point: Group A/ AF-33, AF-19, AF-26, Group B/ AF-38, AF-34, AF-21, Group C/ AF-46, AF-49, AF-37, AF-30, Group D/ AF-50, AF-2, AF-31, AF-23, Group E/ AF-5, AF-9, AF-29. These were gun-boats of one type or another; I am not certain whether they were AFP gunboat versions of the MFP, or converted civilian vessels. Information that this unit was assigned "MFP" vessels may indicate AFP gunboats.
6) The 21st Ladungs Flotilla appears to have been assigned primarily MFP vessels plus some LAT vessels. The MFP's were the "standard" German assault landing craft, while the LAT appear to have been small civilian vessels converted to gunboats.
7) The 24th Ladungs Flotilla appears to have been assigned SAT-5, SAT-6, SAT-7, SAT-8, SAT-11, SAT-15, SAT-18, plus several MFP, several AFP, several MNL and some Seibelferries. The SAT were apparently larger civilian vessels converted to gunboats. The AFP were gunboat versions of the MFP. The MNL were supply lighters similar in size and design to the American/British LCM, although unarmoured. The Seibel-Ferries were catamaran landing craft converted from heavy bridging pontoons; this unit left several in Finland a month earlier which had been shifted to Lake Ladoga; the ones left in Finland were the FlaK variants with 88mm and 20mm guns. The Seibel-Ferries used in this landing may also have been these versions, and might account for the AA guns captured by the Finns during the battle.
8.) The 13th Ladungs Flotilla seems to have been assigned a mixture of MFP and MP (motorboats). This unit was assigned to coastal Estonia/Lithuania evacuation duties prior to Tanne Ost, so it may not have been at full strength. The motorboats may have been assigned to allow evacuation from areas not accessible to the MFP's; rivers, canals and such.
In addition, as jpipes stated, at least two tugs took part in the raid (as they were lost) as well as several B-class boats (were these the seibel-ferries??). The tugs may have been used to tow the Siebel Ferries, as they might not have been able to maintain fleet speed during the voyage (while the other vessels could). All of the Ladungs Flotillas also had support craft (generally converted freighters) which may or may not have participated; some of these were mini-FlaK ships as well as supply ships.
The large numbers of minesweepers are probably beacause Suusaari was the linchpin of the biggest minefield in the gulf of Finland, specifically laid almost all the way across the gulf in order to bottle up the Russian Baltic Fleet. Finnish foces seem to have used primarily small wooden-hulled gunboats (VMV class) in the region for the same reason. Two of these VMV boats were in the harbour at the time of the invasion and were sunk by the Germans (VMV10 and VMV14).
One can only presume that the German landing flotillas were understrength or only partially assigned to this attack, as their numbers are slightly excessive for the forces carried. The land forces, including artillery, would have needed about 15-20 MFP to complete the landing. The units involved had something on the order of 60 MFP, MNL and SF available, plus motorboats (MP), gunboats (SAT/LAT) and artillery landing craft (AFP). They also had approximately 162 Leichte Sturmboote, which presumably would have been launched from MFP or SF vessels away from shore.
Kapitan Zur-See Mecke seems to have been the commander of Sonderkommando 7000 at this point in time; does anyone know if this was the code name for the Operation Tanne forces, or was this a separate unit from which he was drawn to command this attack?
The parent command for the Marine forces participating in the attack was also assigned the following units, which may be the origin of the unknown engineer and "luftwaffe" FlaK personnel and the "poorly trained" 5th company of MAA 531 in the attack:
Marine-Einsatz-Abteilung Ostsee (Prisoner Battalion)
The sound detector unit may have been part of:
1st or 5th Marine-Flugmelde-Abteilung
or a detachment of the Luftwaffe Flugmeldemess-Stellung Tutters radar post located on the nearby island of Tytarsaari.
I would appreciate any other information that anyone may have about any of the units listed.