For babies born preterm, the INTERGROWTH-21st group have published standards for growth based on predominant breast feeding.
https://intergrowth21.tghn.org/articles/new-intergrowth-21st-international-postnatal-growth-standards-charts-available/

Indeed those cases tend to be more complex, require special support. Preterm and LBW babies tend to be admitted in NICU (neonatal intensive care unit).

-For LBW baby you can refer to Infant Feeding in Emergencies Module 2 Version 1.1 for health and nutrition workers in emergency situations. Pp 55-56. This can be adapted if you are not in emergency setting, but the same principles really apply, which are that the mum needs to express as soon as possible after the birth of her baby. Even if the infant is able to suckle directly at the breast, he/she will probably require supplementation with mother's expressed milk at the breast with supplementer to top up the amount ingested or by cup, syringe, dropper. In more severe or less stable cases, a nasogastric tube may need to be used. This will depend on how preterm the infant will be in term of Gestational Age or birth weight (definitions found on WHO website). Again lots of useful info in the booklet on hand expressing (pp 121-122) and cup feeding (pp 119-120 ). UNICEF Baby Friendly UK has a video showing how to express milk, but probably more adequate for our settings in the UK, but some really useful visual tips on the technique of expressing.
-Cleft lip/palate. The Academy of Breastfeeding Medicine has a clinical protocol for BF babies with this orofacial problem (#17). How to help or give messages will depend whether the problem is just CL or CP or CLP. Again the protocol is addressed for health care workers/professionals in a more developed setting, but can be adapted. The Children's Minnesota have published a useful education sheet https://www.childrensmn.org/educationmaterials/childrensmn/article/15843/breastfeeding-an-infant-with-cleft-lip/. Overall parents need clear instruction and lots of help, as I experienced in Africa when working with these children and their mothers. Usually individualised plan is the best.

I hope this helps.

There are guidelines for different circumstances, and cleft palate versus LBW/ prematurity should be treated separately (although they can co-occur!)

Cleft palate:
The cleft may or may not be associated with another underlying congenital problem. In the circumstances of a child with a cleft palate but who is otherwise well, the role of feeding is to improve nutritional status, possibly in preparation for surgery if surgery is available. The methods of feeding are dependent on the size of the cleft and whether the child has a safe swallow reflex, and is likely to choke on the feed and aspirate milk. Often lip clefts interfere with latching. Each child is different, and will need a full assessment of how they feed, and the best way to do this for them. If the cleft is very severe, and the swallow is unsafe, the child may need feeds via naso/oro-gastric tube. This may be required until they have surgery (if surgery is a possibility) and they may tolerate solids better than liquid feeds, although introduction of solids must not be done too early. There are several guidelines regarding advice on how to feed these children:
http://www.health.vic.gov.au/neonatalhandbook/congenital/cleft-lip-and-palate.htm
http://www.seattlechildrens.org/clinics-programs/craniofacial/patient-family-resources/cleft-feeding-instructions/
The weight gain aimed for should be similar to a child without a cleft palate (according to WHO growth charts) unless they are malnourished, in which case aim for a steady weight gain (same as other term malnourished children < 6months).

LBW / premature neonates
LBW and premature neonates will have different capabilities of feeding. Again, LBW and prematurity often co-exist but will not always. Often in low-resource settings there isn’t the possibility of differentiating between which of these children are LBW and which are premature due to the skills of staff present when evaluating the child.

Feeding from birth:
It is often not possible to differentiate between LBW and prematurity due to resources available. Due to this, many NGOs have implemented guidelines based on weight rather than gestational age. These vary, but the message is similar, and is based on resources available. For example, babies with a birth weight <1.25kg may be started on IV fluids, instead of feeds at birth. Usually this is done for 24-48 hours, and then feeds gradually introduced over a couple of days. This is context dependent, as many of these circumstances will not have availability of IV fluids. Any baby <34 weeks gestation will have trouble feeding immediately, and as such requires additional support. Practically, I usually see what the baby can do and use a graded approach. If the baby is trying to suck, then try breastfeeding. They will likely need supplementary feeds, and will get tired easily, so it is important to not exhaust the baby and use up all of their energy trying feed. Mothers should be encouraged to express their breastmilk rather than using formula, as small babies are especially sensitive to complications from using formula. If they can take supplementary feeds using a spoon / paladai then use that. Some areas use syringes but these increase risk of choking in a small baby especially as their suck reflexes are less developed. Otherwise they will need an NGT or OGT to support feeds. Smaller babies need feeding more frequently (around every 2 hours) and this is very tiring for them – as such they need an NGT / OGT to support the feeds.
The volume of feeds is increased over the first few days of life, based on the baby’s birthweight (always use the maximum weight). Usually they start on 60-80ml/kg/d, increased by 10-20ml/kg/d up to around 160ml/kg/d.

Managing malnutrition in LBW / prematurity
If your question is around managing malnutrition in these neonates, the same principles apply as to any other neonate with re-introducing feeds, with two added points. Firstly, think of feeding methods as they are more likely to have difficulty sucking / latching and may require supplementary feeds, as described above. Secondly, because these children have a tendency for hypoglycaemia, hypothermia and dehydration more than any other child, they need to be monitored more closely.
A LBW baby may be fully able to feed, at the same ability as a fully-grown neonate. If a child is LBW, but is a term neonate, they may be able to feed normally (i.e. fully breast feed). If monitored from birth, we can use the growth charts, and watch their weight, to check is it is improving along whichever growth centile they are on. The cause of LBW should be explored (including congenital infection, maternal malnutrition) as these can be managed to improve the child’s nutrition. If the mother is malnourished, her diet can be supplemented to improve and support her breastfeeding.

What I’ve found to be particularly effective is employ local women who have had children themselves, to provide support in the hospital / community with breast feeding as they are better able to communicate with local women when re-establishing feeds. Re-establishing breastfeeds is especially difficult but is usually possible.
In addition, don’t forget to monitor temperature and blood sugars (if available). Kangaroo mother care is the best way to improve feeds, maintain temperature, increase mother-baby bonding and reduce risk of sepsis. It is also very resource efficient. See here: http://apps.who.int/iris/bitstream/10665/42587/1/9241590351.pdf