How does the active verb "veniunt" work with the word "consideranda"? Almost like a periphrastic? As I have translated below:
"Ac initio quidem duo principalia decreta ante omnia consideranda veniunt"
And indeed in the beginning, two principal decrees must come to be considered before all things.
Or how about, "Ut idem significet quod Ex Patre datum habere?"
Something like: "That it signifies the same as to have (having been given) been given from the Father?"
The verb veniunt doesn't work as directly with the gerundive (future passive participle) as you think. Omnia consideranda is "everything that must be considered", so it should be more along the lines of:
[These] come before everything that must be considered.
You can argue that the meaning is practically the same, but I think there is a meaningful structural difference. However, it is possible that I am not simply familiar with this kind of construction, especially if it's post-classical.
I'm not sure how to read datum habere here. It sounds like it could be the same as dedisse, which is active in meaning. Your reading is passive, and it would work better if habere was replaced with esse. Further context would probably help here. Where are the quotes from?
As pointed out by Joonas, it is VERY important to give the relevant/full quotes (at least, in these cases). Otherwise, the poster can receive contradictory feedback. For example, Joonas answered as Cicero would probably did. Indeed, in Classical Latin the only interpretation/analysis of the first example is the one given by Joonas. However, it is the case that the construction haec consideranda veniunt is typical of the Latin written in Early Modern Europe (e.g., cf. The Roles of Latin in Early Modern Europe), where the verb venire can be used as a sort of auxiliary verb with the gerundive consideranda, which is analyzed, like in Late Latin, as a future passive participle ('these things should be taken into account').
As for the second example, I agree with Joonas: the verb habere is used as an auxiliary verb in a compound form with a participle (datum), like in Romance languages (e.g., Cat. 'haver donat'; cf. Lat. dedisse).
