Is there any special term for an unconsecrated or not-yet-consecrated church, chapel, cathedral, etc.?
Term for an Unconsecrated Church
I believe the term you are looking for is an oratory. Chapels within churches are normally not consecrated, but blessed, seeing that the entire church structure is already consecrated. Their altars are nevertheless consecrated. Chapels outside of churches are generally not consecrated but as in the case of hospitals and ships or wayside chapels and are considered oratories.
The term chapel is probably still in vogue here and there and will also fit the bill. In my experience, an unconsecrated or yet-be-consecrated-church is generally referred to as a church. This would probably be the same for a cathedral that is yet to be consecrated: it would be called a cathedral notwithstanding.
Here is what the Catholic Encyclopedia has to say about oratories:
(Latin oratorium, from orare, to pray)
As a general term, Oratory signifies a place of prayer, but technically it means a structure other than a parish church, set aside by ecclesiastical authority for prayer and the celebration of Mass. Oratories seem to have originated from the chapels erected over the tombs of the early martyrs where the faithful resorted to pray, and also from the necessity of having a place of cappella or capella. In this tent Mass was celebrated by the military chaplains (capellani). When at rest in the palace the relic likewise gave its name to the oratory where it was kept, and subsequently any oratory where Mass and Divine service were celebrated was called capella, chapelle, chapel. The word is first found used in this sense by Marculfus (seventh century), who gives the above etymology, an explanation which has been generally accepted ever since, though Durandus ventures upon an alternative derivation, to wit, capra, because the tent above mentioned was made of goat-skins. Another, but improbable, derivation is cupella, a domical or cup-shaped monument. The canopy over an altar was also at one time called a capella. In ecclesiastical documents the main sanctuary of a church is often termed the capella major, to distinguish it from the side-altars (cf. St. Charles Borromeo's "Instructions"). In Spain the sanctuary containing the high altar is to this day called the capilla mayor. The thing is, however, much more ancient than the name, and Thomassin quotes numerous early references to oratoria, sacella, and eukteria. In dealing with the subject a large number of different kinds of chapels are to be considered, which vary according to their connexion with, or dependence upon, other buildings, or to the specific uses to which they were put. Thus we have chapels which structurally form part of a larger church, those which are included within other buildings not churches, and those which are entirely separate and detached. We have also papal, royal, episcopal, votive, wayside and mortuary chapels. It seems best for the purposes of this article, first to trace the origin and development of chapels in general, and then to deal with the different kinds, according to their special uses, and under their respective titles, in alphabetical order.
Ecclesiastical law as to chapels
The present-day law of the Church, while placing no restriction on the erection of chapels that form part of a larger church, lays down very definite regulations respecting any that belong to the category of private chapels. This applies, however, only to those intended for the celebration of Mass; there is no restriction whatever as regards the setting apart of a particular chamber in a private house merely for purposes of private prayer and devotion. But for a chapel in which Mass is to be said, canon law legislates very strictly. Cardinals, bishops (even titular), and regular prelates, are allowed the use of a private chapel by right; for all others a special indult is required. The ordinary of the diocese can give the necessary permission for the chapel or oratory of an institution such as a religious house, an orphanage, hospital, workhouse, or prison, such chapels being usually public or semi-public. But for a strictly private chapel in a private house, intended only for the convenience of the inmates of the house, a papal indult must be obtained, and such indults are only granted for sufficient reasons, e.g. distance from a church, permanent ill-health of a member of the household, etc. With regard to the fulfilment of the obligation of hearing Mass in such private oratories, the ancient law of the Church was that the obligation could only be satisfied by attendance at the parish church. The Council of Trent somewhat modified this rule and since then theologians have differed as to what was the exact law. To settle the matter, Leo XIII, in 1899 (S. R. C. no. 4007), decided that;
the obligation can be satisfied by any one in all public or semi-public chapels to which the faithful have access; but
it cannot ordinarily be satisfied in a strictly private chapel by any persons other than those for whose convenience the chapel exists.
This rule, in practice, is capable of a somewhat wide interpretation, and the indult by which the permission for the chapel is granted usually extends the privilege to various other persons, e.g. relations, guests, servants, etc. All places of worship in England belonging to Catholics, like those of other religious bodies outside the Established Church, were formerly termed "chapels."