1) One of the contractor quote me the price but didnt quote for fixing the leakages, i heard that he is reluctant to fix leakages.....do you think i should award the job to him since "fixing the leakages" is the main concern here.

Ask him to make fixing the leakages as 1st priority! need to get it into his brain before he carried out. of course, re-quote the price if needed for black n white purpose.

2) The parquet upstair came out pieces by pieces, as such, he recommended me to change to all tiles. Is there a shop that sell parquet that i can actually stick it back myself? Or any recommended shop for cheap tiles with average quality?

Maybe, but if the pieces comes out, probably can buy the glue selling in hardware shops. It'll do the work.

3) For grille, he quoted me about RM3000 for normal type of steel. Is this reasonable?

Need the total measurements.

4) For painting of whole house with cheap paint, he quoted me RM3350 (this is inclusive of painting exterior with dulux weathershield). But my exterior is still clean as the seller paint it exterior before handling over to me, so i decided not to paint the exterior.

So what is the problem here?

5) Buying 4 doors with aluminium coating (for washroom so that it will last longer) - RM1040, reasonable?

Ok, it's around tat price in penang. i think its ok.

6) if i engage a contractor, what are the payment like? do i need to pay deposit or i only pay when the work is done? How about warranty? If the leakage still persist after fixing, do i get warranty that they will fix it till right? Do i need to pay additional?

Dont pay ALL sum, dont pay until they ask you too. If they want full payment, say NO. Payments paid are relative to the jobs done OR they need to buy materials and stuffs.

7) I need to get receipt to them everytime i pay or i need to get them to sign my payment voucher everytime they received the money?

Do get the receipts after making last payment.