if it is not complicated, you can also get contractors to find for you, turnkey project... everything under the contractor

2. approval depends on your plan/idea.. of course you need to comply to the building bylaws. but if comply.. not really hard to get approval

3. you're a owner, of course they will try best to please you. but of course your design have to be practical, like you cant make you're building float out of thin air
they will of course advise you based on practicality and buildability.. but u can ignore the "artistic" part as please

majlis law and national building by-law
these things shall be observed by the architect. you need not worry. but you should note on the by-laws such as building set back from boundary. some by-laws may be imposed on special conditions such as if ur house is in heritage zones, or beside highways.

10% for just archi is higher than usual.. most includes engineering fees into it.

if your house is simple, just engage pelukis plan only.
Spoiler tips: if you couldn't care less about the design, insiders in the local authorities might got cheaper contacts. just for the sake of submission and approvals.

but if building is excessive, engage better architect.. you get what you paid for