All states have enacted the Uniform Child Custody Jurisdiction and Enforcement Act, which provides the rules for which court (the courts of which state) has jurisdiction initially to issue, and later to modify, child custody awards. The UCCJEA rules normally are not displaced by an agreement of the parties.
Under the UCCJEA, even though you moved out of state, California, as the first state with proper jurisdiction to issue a custody award, would remain the proper state to make modifications, so long as one parent continued to live here. In theory, if the child had very little continuing connection with California (Father ceases to exercise his custody time or his time becomes token), a California court could determine that it should surrender jurisdiction to the state where the child is living, and where more information about the child's interests is located. However, on your facts, with the child continuing to spend significant time in California, it is not likely that a California court would decide to terminate its jurisdiction.
In light of this, point #1 is probably meaningless, since the UCCJEA provides the rules. Since "home state" is defined in the UCCJEA, making a statement about the future home state in the custody order is also probably pointless. In any event, "home state" jurisdiction is usually important for initial jurisdiction, while the issue in your case in the future will be jurisdiction to modify. So point 2 is neither necessary nor, most likely, useful. No. 3 is a statement of fact about the future. However, when the issue arises, which is likely only after the child's connection to California is no longer very significant (until then, California is clearly the state with jurisdiction) the "actual" facts, not the recited facts in the prior order, will be important.
So points 1-3 are not useful, really, even to your husband in his goal to keep jurisdiction in California. A recitation that California is (now) the home state is useful.
On the other hand, it probably won't make much of a difference agreeing to the language, since California would retain jurisdiction to modify the current order even if you remain out of state for a long time, so long as Father continues to live in California and have any significant contact with the child.
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