1. is the point of entry water filter possible to install? where?
Depend on management decision. Most would say no.

2. can put washing machine at the balcony? it is designed to place air-cond compressor
Yes, if there is water source/pipe and electric source. Hacking part need to ask management.

3. can put cooker at yard?
If it is in your unit area and doesn't affect the appearance of the condo, normally it is okay to have a wet kitchen. Unless you want to hack the wall, then need to ask the management.

4. can install window at yard?
Depend on your yard design if it requires wall hacking. Wall hacking-related better to consult management as it might affect the building structure.