How flags work - First, the individual flags. Each number 2^n is a flag because of how it’s represented in binary - 2, 4, 8, 16, 32, etc up to 536870912. In binary, the numbers start at 000000000000000000000000000010 (2) and go up to 100000000000000000000000000000 (536870912). This is the first list from the OP, it’s the list of 29 unique flags that structures can have checked as their types. Note: the last flag is always 0, this is why there are only odd numbers.
Structures can have any number of flags checked (i.e. they fit into multiple categories). This is done by simply adding the flags together - for example Fence Foundations fit into 3 categories, 16, 4194304, and 8388608. In total they add up to 12582928 which is a number representing all 3 flags. In binary, this number is 00000110000000000000000010000 - 3 flags checked. This is the second list from the OP.
The snap point match groups similarly use flags. If there is ANY flag match between the two groups it is considered a match, so for example a hypothetical match group 58 (2+56) would match with things from either group 56 or group 2; this would include an object marked as match group 10 (2+8) for example.
In the editor, snap points are marked as either to points (the object that already exists in the world), the from point (the object that you’re adding onto the existing structure), or both. If a single point is marked as to and from, it can only be used as one or the other, so it is often better to ‘overload’ them that way, but you need to ensure the offsets and rotations and such will align properly if it is both types of point.
When determining if it can make a snap connection, first it looks to see if there is a snap group match between the two structures. If there is a match, it checks the “to point snap type flags” from the structure marked as ‘attach to point’ and compares it against the “structure snap type flags” of the structure marked as ‘attach from point’ and looks for a match there. A match here is determined by ANY flag match, not all flag matches! So if you put 258 (2+256, two flags) for the ‘to point snap type flags’, it would match with any structure that matches either 2 or 256, or both. A 0 means it will snap to anything in its match group. If this is causing it to snap to something it shouldn’t, that is where the “to point snap type exclude flags” comes into play, which excludes only structures that match ALL the flags (so 258 would exclude just pillars, not foundations, spiked walls, or elevator tracks), and a 0 means nothing is excluded.
One thing I don’t know is if the flags actually have a tangible game effect, or if they are purely used in the snap matches. It’s possible that, say, changing walls to have the first flag (foundations) might cause them to actually DO something else.
So to directly answer your questions, 6114 as the “to point snap type flags” means it will connect with objects in either the 2048 or 4096 group, so anything related to irrigation basically. They are marked as ‘to’ and ‘from’ in a single point so that you can’t use that snap point twice, you can’t snap it onto an existing pipe and then use that same connection to make a new pipe from that same socket (you could go in the other direction but that’s another snap point). You cannot snap a reservoir onto a tap because taps only have a ‘from’ snap point (can only put them onto existing water structures). You can actually snap a tap onto/into a reservoir, but it doesn’t irrigate so it’s pointless (this would be fixed by making reservoir have only a single snap point that functions as to and from).