1) So for charging them, do you make a charging port for every module or just do 2 modules per charging port and then do parallel charging? which is better?
Yes, each module can be charged independently. In case you remove one for testing, etc. So each module has a charging port. When you install the module and put it in parallel with the other, then the two charging ports should go in parallel, and you can connect one charger to charge both, or connect two chargers in parallel, one on each port. Or you can have a separate charging port in a convenient location that connects to both charging ports in parallel.
The other module pair that is in series, must have its own port, and you cannot charge two serial modules in parallel (unless you install hefty switches or contactors to rewire for charging, and not forget to switch it). However, you can have one big charger 2x13x4.2V = 109.2V and charge the whole system with a single charger. I still prefer at least two chargers, each 54.6V, in series, one for the upper pair and the other for the lower pair. If you lose a charger in a trip, you still have the other one that can charge any pair.
I will also put an ammeter with LED display on each module, as they can point to problems. Also one LED voltmeter that can measure the module voltage, or using switches measure the voltage for each group of cells. So the switches will allow 14 readings by the voltmeter. One for each group and one for total. Occasionally upon charge and discharge one must check all 13 groups in the module. If there is one that is different, then it probably means one cell has gone bad. You need to replace that cell in the group as not only it reduces total energy storage disproportionally, but could result in future safety issues like a fire.
If you plan to go 26s30p, then I would suggest you split that into 6 modules: 2 series x 3 parallel x 13s10p. The modules become smaller and may be easier to install. Also, if you lose a module (due to a bad cell), you can disconnect two modules, and still have 4 working which gives you 2/3 range. On the other hand if you had 4 modules total, and one goes bad, your range drops to 1/2. Also if you have one or two bad cells in a group, or you are unsure, you will have to open all cells in the group to find which one it is. In a 13s15p module, you will have to open 15 cells. In 13s10p, you open 10 cells.