I want to combine these two names hana lee/ hana leigh to make a first name. Want to know if its possible. One is english oriented n the other is arabic.

Hana means happiness/joy/one/happy/flower
Lee/Leigh means healer/poetic/field-pasture

If i combine like that would it mean happy healer? Like hana healer? Or happy poetic? Is it allowed to combine the names nonetheless even if the meanings dont blend but have good meanings?

There is no interaction between the two names, the name's meaning would be "Happiness Lee", which could be considered to mean that Lee is happy or is a bringer of happiness. If we use Lee with the meaning of "Healer", the name would "Happiness Healer", which does not have any specific meaning, but you can give it a meaning yourself. There is no issue with using two names even if each has its own independent meaning, many names used by Muslims are this way.

So its okay to have two attributes like happy healer. Or happiness and healer. Right. Same goes for hana kim and hana lynn?

Yes, it is the same for Hana Kim and Hana Lynn.

Secondly,I wanted to know since theres variety of meanings to each name from different customs. Do i have to choose one that i like or one thats in arabic for lynn kim or lee?

There is no need to use an Arabic name or an Arabic meaning/pronunciation of a name. Muslims in Turkey and Persia, for example, usually use non-Arabic names from their own languages. The only requirement for baby names in Islam is that their meaning should not be against Islam's teachings (thus a name meaning "son of God" is not acceptable), which means most names from languages around the world are acceptable for a Muslim child.

There is no such thing as "Islamic" numerology, in Islam all fortune-telling is considered false, regardless of what methods are used; it doesn't make a difference whether the fortune-teller uses horoscopes or the Quran, both are equally forbidden because in Islam only Allah knows the Unseen, and any practice that tries to tell the future or the unseen nature of something (such as a name's effects) are considered false.

As you said, the only factor that should be considered is whether the name has a good meaning. If it is so, then there are no other considerations according to Islam. In Islamic cultures in Turkey and Persia, people choose names because they like a name, they do not believe in lucky numbers and other non-Islamic concepts.

Istikhara is meant to be used when you do not know if something is good. But with baby names, since all baby names with a good meaning are good, it is not meant to be used here. If you liked two baby names but did not know their meanings, you could do istikhara to decide which one to choose. Istikhara is for situations like this where you do not have the necessary information to know if something is good.

Yuli as you mentioned is a variant of Julia/Julius, which is considered to mean "youthful one". The true origin of this name is not known; the meaning if "first beard" or similar meanings are only guesswork. Since the common modern meaning is "youthful one" and since it is a good meaning, it is acceptable to use it.

The original Latin form is Julus, from which Julius comes, and is feminized to Julia. Yuli could be an Eastern European shortened form for either Julius or Julia, for this reason it is acceptable for both boys and girls.

Julius could also mean "son of Jove" as you said, it is one of the proposed meanings, but as said before, it is not certain. What matters with a name is what we mean by it. If one day we find that there is a language in which Muhammad has a bad meaning, it doesn't make Muhammad a bad name.

Yuli is also a Nahuatl (Aztec) word meaning "to live", "to resuscitate", which is a good meaning. You can also use Yuli as a variant for Eulalia which means "well-spoken" as you said. There is no issue with this name from a religious perspective (unless you use it with the pagan meaning).

Thus, as said, what matters is our intention. If we use a name for a good meaning, it will be a good name.

To avoid people's criticism, you can use the name for the Aztec meaning or as a variant of Eulalia, instead of telling them it is from Julia/Julius, as some Muslims may take issue with using a name that has anything to do with the Romans (though technically there is nothing wrong with using the "youthful" Roman/Greek meaning).