Patio door keeps / striker plates

The keeps match your mechanism so swapping wouldn't change anything and they tend to be a set size, you could try swapping out the rubber seal for a thicker one this is the cheaper option, there may be a possibility that the doors maybe out of alignment, with you saying the keep is stopping the door closing properly, but without talking to you to ask other questions it's difficult to say, definitely try the rubber seals 1st they pull out easy

I think what your trying to do is unlikely to fix the problem. The keeps will match the mechanism, rather than being separate parts. I would guess that something else is the problem if its not fully closing. Check the track for any debris, and ensure everything is clean and clear, it's surprising how a small amount of debris can sometimes stop a door.

Yes you can chnage the keeps but like for like so would need to go and have a look at this job before anything. Hope this helps

The doors are full adjustable on the hinges which once tweaked (usually an Allen key) will reduce or increase the closing gap. There are numerous adjustments that can be made including raising or lowering each door. Also depends if it’s a hook bolt or “rollers”? A good locksmith would get that door working perfectly.