Depend on a whole lot of variables. But they are essentially the same aircraft and have very similar figures, and all your questions will be effected by which engine you have fitted to each.
The 205 A1 is essentially a 205 fitted with the 212 running gear, therefore they have the same speed limitations: normal cruise at 100 kias, vne at 120. Fuel burn depends on donk fitted as does lifting performance. Both can be fitted with the same range extenders, etc.
205 A1 (MAUW 10,500lbs) is often fitted with a -13 or -17 donk. Both will allow MAUW hover IGE at the figures you quote, but the -13 struggles OGE and is obviously outperformed at HDA. The -17 is good to quite high DAs. Fuel burn is 600lbs/hr (as low as 580 in the cruise) for the -13. I cannot recall the -17 burn.
212 (MAUW 11,200 lbs) has the PT6 in two versions, -3, and -3B. Same story as above, both will do IGE at MAUW at the DAs you mention. Same as OGE, the -3 will start to strugggle OGE, and the -3B begins to out perform at higher DAs. Fuel burn for the -3s is 640lbs/hr, but can be up to 700 - 740 for the -3Bs and has a noticeable affect on range.
for lifting, the body weight differences actually gives the A1 the advantage, generally by about 100 to 200kg despite a lower MAUW. But generally, they are pretty similar unless you compare say the -17 A1 at altidude to the -3 212, or vice versa.
Our old chief engineer used to say that due to the expense of the Lycomings, the 212 was only about 10-15% higher costs even though it is a twin. But I believe that with the increase in ex mil UH-1s, the Lycoming costs may be getting better.
My prefernce is always for the twin, especially doing ext load ops, because once the load is gone, the 212 will not come down and mess with your ground crews - or your pilot's next of kin.