They sure both look Asian to me. I think you should maybe replace both with trees properly identified, but because they are probably Asian they will probably adequately identify themselves very shortly. If they are Asian you don't have to worry about speeding their fruiting- they may even bear next season. The reason I would consider replacing them is because fireblight can be heartbreaking and even if you graft on other varieties the trees may be susceptible unless you have no tender new wood from original trees. On the bright side, many Asians are fireblight resistant. Multiple leader pear trees are common in commercial production in the west coast. Here in the east they are mostly grown to a central leader- I guess we don't get quite as much FB. Festooning (pulling branches below horizontal)the branches may encourage early fruiting but it will not encourage a great scaffold structure. I sometimes use the method for trees I plan to train to a weep or for Euro plums just to get them into fruiting mode but many types of pears should not be trained this way in my opinion. None of the Asians I grow would be good candidates for this, they fruit so early anyway. Asian and European pears are mostly pollen compatible- the problem can be timing of bloom. That issue will sort itself out as well when trees begin to flower.

You don't talk about more branches the better in 4 in 1 trees- you just don't have a choice. I hate these trees- they are a virtual impossibility to train well. Each variety has it's own level of vigor, but in Asian pears and peaches this might not be as big a problem as with apples. Apples are all I have experience with in this form. It looks like branches were already cut back for shipping. What you need to do during the growing season is keep the 4 different varieties growing at about the same pace so one doesn't dominate the tree. I can see that will be an issue for the peach for sure, with the top branch in position to dominate. Pinch growth that eminates from where branches were cut to encourage dominance of a single leader while developing less vigorous (smaller) secondary branching off it. Each variety should be treated like an individual central leader tree in terms of form. The central leader being like a trunk with smaller branches (no more than half diameter) coming off it. Also pinch back as needed to keep the different varieties in balance. Pinching means that you're removing as little growth as possible to stear energy where you want it, so it won't really retard overall growth. If you let the trees go without guidance for even one season you may loose control with certain varieties dominating the tree and starving out other varieties. Anyway, that's my opinion. My experience is primarily with 4in1's that have been badly trained and I have to try to straighten things out later. I would never produce a tree like this, much better to alternate varieties by tiers off a central leader, placing most vigorous varieties at base. In other words, new varieties are grafted as extensions of the trunk as the trees grow up. This wouldn't work well for peaches, though.

I would remove that big stalk that grows kind of sideways from the base of tree. The tree would have a nicer vase shape, and you would also have greater access to the ground around the base of the tree. I have a multi-trunk Serviceberry (Amelanchier x lamarckii) in the middle of the front garden, and enjoy its upright growth form and airy canopy. This allows me to more easily grow perennials and bulbs underneath and around the tree. While (if) you're pruning, also remove prune any dead, broken, crossing, or diseased branches.

I'm not sure what the purple patch could be, but the plant looks like it is in some terrible soil! Looks very peaty and compact. It is even pulling away from the edge of the pot. I recommend you repot it into a better draining mix as you are virtually guaranteed to have problems if you keep it in that soil. Also please don't water plants with only a litre of water on a schedule. They need enough water that it fully drenches all of the soil and the root zone and comes running out of the draining holes. Which it might do now with a small amount of water because it's so compact. You should also only water when the soil is dry down to a certain length. Either by sticking your finger in the soil or using a wooden dowel or skewer. I haven't owned a pachira for a long time, so I'm not sure on what their proper care is, but that soil is not looking good.