Answers

Yes it is possible but not practical. Technically you can do it and you can put plastic laminate over plastic laminate. But the  layer your covering has to be super clean, abraded and all surfaces must be accessible. Edges and returns can be  more than a challenge. Any drop-ins likes sinks and cooktops have to come out and be reset after the new surface is in place. Results may be less than desirable.

 That being said, the cost of new laminate tops are one of the most inexpensive, so it would be better to just install new ones. You will be happier with the results.

No.  I don't think that is a good idera.  You are not going to be happy with result.  Hold off spending money doing what you are recommending until you have money to do it the right way.

Philip Anderson

HDR Remodeling Berkeley ca

It can be done but results won't be as good as countertops build in the shop and installed after it. 

Many factors involved to consider. What laminate surface you have on existing countertops, do you have seems, what tipe of backsplash you have and tipe of edge on your countertop. 

After all, my suggestion would be. Add another 30% and get new countertops made right way. Or add another 50% and get lover grade solid granite countertops what brings you much better value. Consider that in any case you will have to remove and reinstall faucet and sink. That is addittional expence that many people dont realize to include in to their budget.

Good luck.

Manny Stiega.

Da Vinci Cabinetry LLC.