Cal FC-DMS11 are merging, although it looks more like an acquisition or takeover given that Metcalfe was very publicly selling off all of his coaching equipment recently.
This appears to be part of a general trend to link youth clubs with professional or adult teams so that they resemble more true academy set-ups. In this case, it appears to be the acquisition of a youth club by a semi-pro or pro team (Cal FC will be playing in NPSL's Founders Cup, which is technically an adult league organized under the amateur US Adult Soccer Ass'n, but it includes some former NASL clubs that appear to pay all of their players).
By contrast, Santa Monica United recently announced the start of a UPSL adult team of the same name, which looks to be more organically linked with the youth club since it appears to be coached by and include players from the SMU youth coaching ranks, although the adult team seems to trace its roots to a previous adult team that was once in UPSL, Sporting Santa Monica. Either way, this looks to be more common as both NPSL and UPSL are growing quickly. At its best, the relationship can be mutually beneficial, providing coaches, training opportunities, and a post-graduate home for the youth club and a place for the adult team players to earn some extra cash (coaching), share field space, and recruit players. At it's worst, it's just another way to leverage pay-to-play. SMU seems like it has a better chance at the former than Cal FC given the ties to current SMU coaches, but we'll see how they both develop.