Am I a candidate for veneers with weak teeth and what steps to take? (Photo)

From the pictures that you have posted I see no problem with getting veneers to improve your smile. The same dentist can address the decay and cosmetic issues. The important thing to understand is that you can get decay around a veneers just as you can get decay on a  natural tooth. How are you going to reduce the risk of decay in the future? This needs to be addressed with the dentist prior to beginning treatment.

yes, u r a ideal candidate for veneers. it will definitely improve yr smile. there is no relation between oral health and veneers, so u can go for veneers. but its my advice to go for veneers followed by other dental work. now come to cost factor, in usa dentist charge from $1500 to $3500 per veneer. but if u want to save money , dental tourism is good option for u. now a days many people avail dental tourism option for veneers . by that u will save almost 80% . for eg. in india $200 per veneer/tooth.

From the photos it appears you would be a candidate for Porcelain veneers.  No need to go to a separate dentistto replace fillings first. that can be taken care of when veneers are prepped.  Cost depends on area you live.Porcelain veneers can range from 1000-3500 per tooth depending on location and doctor

The condition of the teeth won't prevent a smile makeover, but some veneers become crowns if the tooth structure is too damaged.  Decay must be removed, and the process of veneering teeth often removes the decay, if not then the prep can become more like a 3/4 crown to include the decayed area.